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Full-Text Articles in Physical Sciences and Mathematics
Ultrafast Investigation And Control Of Dirac And Weyl Semimetals, Christopher P. Weber
Ultrafast Investigation And Control Of Dirac And Weyl Semimetals, Christopher P. Weber
Physics
Ultrafast experiments using sub-picosecond pulses of light are poised to play an important role in the study and use of topological materials and, particularly, of the three-dimensional Dirac and Weyl semimetals. Many of these materials’ characteristic properties—their linear band dispersion, Berry curvature, near-vanishing density of states at the Fermi energy, and sensitivity to crystalline and time-reversal symmetries—are closely related to their sub- and few-picosecond response to light. Ultrafast measurements offer the opportunity to explore excitonic instabilities and transient photocurrents, the latter depending on the Berry curvature and possibly quantized by fundamental constants. Optical pulses may, through Floquet effects, controllably and …
Search For Low-Mass Dark Matter With Cdmslite Using A Profile Likelihood Fit, R. Agnese, T. Aralis, T. Aramaki, I. J. Arnquist, E. Azadbakht, W. Baker, S. Banik, D. Barker, D. A. Bauer, T. Binder, M. A. Bowles, P. L. Brink, R. Bunker, B. Cabrera, R. Calkins, R. A. Cameron, C. Cartaro, D. G. Cerdeño, Y.-Y. Chang, J. Cooley, B. Cornell, P. Cushman, F. De Brienne, T. Doughty, E. Fascione, E. Figueroa-Feliciano, C. W. Fink, M. Fritts, G. Gerbier, R. Germond, M. Ghaith, S. R. Golwala, H. R. Harris, N. Herbert, Z. Kelsey, A. Kennedy, A. Kubik, N. A. Kurinsky, R. E. Lawrence, B. Loer, E. Lopez Asamar, P. Lukens, D. Macdonell, R. Mahapatra, V. Mandic, N. Mast, E. Miller, N. Mirabolfathi, B. Mohanty, J. D. Morales Mendoza, J. Nelson, H. Neog, J. L. Orrell, S. M. Oser, W. A. Page, R. Partridge, M. Pepin, F. Ponce, S. Poudel, M. Pyle, H. Qiu, W. Rau, A. Reisetter, R. Ren, T. Reynolds, A. Roberts, A. E. Robinson, H. E. Rogers, T. Saab, B. Sadoulet, J. Sander, A. Scarff, R. W. Schnee, S. Scorza, K. Senapati, B. Serfass, D. Speller, C. Stanford, M. Stein, J. Street, H. A. Tanaka, D. Toback, R. Underwood, A. N. Villano, B. Von Krosigk, S. L. Watkins, J. S. Wilson, M. J. Wilson, J. Winchell, D. H. Wright, S. Yellin, Betty A. Young, X. Zhang, X. Zhao
Search For Low-Mass Dark Matter With Cdmslite Using A Profile Likelihood Fit, R. Agnese, T. Aralis, T. Aramaki, I. J. Arnquist, E. Azadbakht, W. Baker, S. Banik, D. Barker, D. A. Bauer, T. Binder, M. A. Bowles, P. L. Brink, R. Bunker, B. Cabrera, R. Calkins, R. A. Cameron, C. Cartaro, D. G. Cerdeño, Y.-Y. Chang, J. Cooley, B. Cornell, P. Cushman, F. De Brienne, T. Doughty, E. Fascione, E. Figueroa-Feliciano, C. W. Fink, M. Fritts, G. Gerbier, R. Germond, M. Ghaith, S. R. Golwala, H. R. Harris, N. Herbert, Z. Kelsey, A. Kennedy, A. Kubik, N. A. Kurinsky, R. E. Lawrence, B. Loer, E. Lopez Asamar, P. Lukens, D. Macdonell, R. Mahapatra, V. Mandic, N. Mast, E. Miller, N. Mirabolfathi, B. Mohanty, J. D. Morales Mendoza, J. Nelson, H. Neog, J. L. Orrell, S. M. Oser, W. A. Page, R. Partridge, M. Pepin, F. Ponce, S. Poudel, M. Pyle, H. Qiu, W. Rau, A. Reisetter, R. Ren, T. Reynolds, A. Roberts, A. E. Robinson, H. E. Rogers, T. Saab, B. Sadoulet, J. Sander, A. Scarff, R. W. Schnee, S. Scorza, K. Senapati, B. Serfass, D. Speller, C. Stanford, M. Stein, J. Street, H. A. Tanaka, D. Toback, R. Underwood, A. N. Villano, B. Von Krosigk, S. L. Watkins, J. S. Wilson, M. J. Wilson, J. Winchell, D. H. Wright, S. Yellin, Betty A. Young, X. Zhang, X. Zhao
Physics
The Cryogenic Dark Matter Search low ionization threshold experiment (CDMSlite) searches for interactions between dark matter particles and germanium nuclei in cryogenic detectors. The experiment has achieved a low energy threshold with improved sensitivity to low-mass (/c2) dark matter particles. We present an analysis of the final CDMSlite data set, taken with a different detector than was used for the two previous CDMSlite data sets. This analysis includes a data "salting" method to protect against bias, improved noise discrimination, background modeling, and the use of profile likelihood methods to search for a dark matter signal in the presence …
Spatial Imaging Of Charge Transport In Silicon At Low Temperature, R. A. Moffatt, N. A. Kurinsky, C. Stanford, J. Allen, P. L. Brink, Blas Cabrera, M. Cherry, F. Inuslla, F. Ponce, K. Sundqvist, S. Yellin, J. J. Yen, Betty A. Young
Spatial Imaging Of Charge Transport In Silicon At Low Temperature, R. A. Moffatt, N. A. Kurinsky, C. Stanford, J. Allen, P. L. Brink, Blas Cabrera, M. Cherry, F. Inuslla, F. Ponce, K. Sundqvist, S. Yellin, J. J. Yen, Betty A. Young
Physics
We present direct imaging measurements of charge transport across a 1 cm × 1 cm × 4 mm crystal of high purity silicon (∼20 kΩ cm) at temperatures between 500 mK and 5 K. We use these data to determine the intervalley scattering rate of electrons as a function of the electric field applied along the ⟨111⟩ crystal axis, and we present a phenomenological model of intervalley scattering which explains the constant scattering rate seen at low-voltage for cryogenic temperatures. We also demonstrate direct imaging measurements of effective hole mass anisotropy, which is strongly dependent on both temperature and electric …
Production Rate Measurement Of Tritium And Other Cosmogenic Isotopes In Germanium With Cdmslite, R. Agnese, T. Aralis, T. Aramaki, I. J. Arnquist, E. Azadbakht, W. Baker, D. Barker, D. A. Bauer, T. Binder, M. A. Bowles, P. L. Brink, R. Bunker, B. Cabrera, R. Calkins, C. Cartaro, D. G. Cerdeño, Y.-Y. Chang, J. Cooley, B. Cornell, P. Cushman, T. Doughty, E. Fascione, E. Figueroa-Feliciano, C. W. Fink, M. Fritts, G. Gerbier, R. Germond, M. Ghaith, S. R. Golwala, H. R. Harris, Z. Hong, E. W. Hoppe, L. Hsu, M. E. Huber, V. Iyer, D> Jardin, A. Jastram, C. Jena, M. H. Kelsey, A. Kennedy, A. Kubik, N. A. Kurinsky, R. E. Lawrence, B. Loer, E. Lopez Asamar, P. Lukens, D. Macdonell, R. Mahapatra, V. Mandic, N. Mast, E. Miller, N. Mirabolfathi, B. Mohanty, J. D. Morales Mendoza, J. Nelson, J. G. Orrell, S. M. Oser, W. A. Page, R. Partridge, M. Pepin, F. Ponce, S. Poudel, M. Pyle, H. Qui, W. Rau, A. Reisetter, R. Ren, T. Reynolds, A. Roberts, A. E. Robinson, H. E. Rogers, T. Saab, B. Sadoulet, J. Sander, A. Scarff, R. W. Schnee, S. Scorza, K. Senapati, B. Serfass, D. Speller, M. Stein, J. Street, H. A. Tanaka, D. Toback, R. Underwood, A. N. Villano, B. Von Krosigk, S. L. Watkins, J. S. Wilson, M. J. Wilson, J. Winchell, D. H. Wright, S. Yellin, Betty A. Young, X. Zhang, X. Zhao
Production Rate Measurement Of Tritium And Other Cosmogenic Isotopes In Germanium With Cdmslite, R. Agnese, T. Aralis, T. Aramaki, I. J. Arnquist, E. Azadbakht, W. Baker, D. Barker, D. A. Bauer, T. Binder, M. A. Bowles, P. L. Brink, R. Bunker, B. Cabrera, R. Calkins, C. Cartaro, D. G. Cerdeño, Y.-Y. Chang, J. Cooley, B. Cornell, P. Cushman, T. Doughty, E. Fascione, E. Figueroa-Feliciano, C. W. Fink, M. Fritts, G. Gerbier, R. Germond, M. Ghaith, S. R. Golwala, H. R. Harris, Z. Hong, E. W. Hoppe, L. Hsu, M. E. Huber, V. Iyer, D> Jardin, A. Jastram, C. Jena, M. H. Kelsey, A. Kennedy, A. Kubik, N. A. Kurinsky, R. E. Lawrence, B. Loer, E. Lopez Asamar, P. Lukens, D. Macdonell, R. Mahapatra, V. Mandic, N. Mast, E. Miller, N. Mirabolfathi, B. Mohanty, J. D. Morales Mendoza, J. Nelson, J. G. Orrell, S. M. Oser, W. A. Page, R. Partridge, M. Pepin, F. Ponce, S. Poudel, M. Pyle, H. Qui, W. Rau, A. Reisetter, R. Ren, T. Reynolds, A. Roberts, A. E. Robinson, H. E. Rogers, T. Saab, B. Sadoulet, J. Sander, A. Scarff, R. W. Schnee, S. Scorza, K. Senapati, B. Serfass, D. Speller, M. Stein, J. Street, H. A. Tanaka, D. Toback, R. Underwood, A. N. Villano, B. Von Krosigk, S. L. Watkins, J. S. Wilson, M. J. Wilson, J. Winchell, D. H. Wright, S. Yellin, Betty A. Young, X. Zhang, X. Zhao
Physics
Future direct searches for low-mass dark matter particles with germanium detectors, such as SuperCDMS SNOLAB, are expected to be limited by backgrounds from radioactive isotopes activated by cosmogenic radiation inside the germanium. There are limited experimental data available to constrain production rates and a large spread of theoretical predictions. We examine the calculation of expected production rates, and analyze data from the second run of the CDMS low ionization threshold experiment (CDMSlite) to estimate the rates for several isotopes. We model the measured CDMSlite spectrum and fit for contributions from tritium and other isotopes. Using the knowledge of the detector …
Directly Photoexcited Dirac And Weyl Fermions In Zrsis And Nbas, Christopher P. Weber, Leslie M. Schoop, Stuart S. P. Parkin, Robert C. Newby, Alex Nateprov, Bettina Lotsch, Bala Murali Krishna Mariserla, J. Matthew Kim, Keshav M. Dani, Hans A. Bechtel, Ernerst Arushanov, Mazhar Ali
Directly Photoexcited Dirac And Weyl Fermions In Zrsis And Nbas, Christopher P. Weber, Leslie M. Schoop, Stuart S. P. Parkin, Robert C. Newby, Alex Nateprov, Bettina Lotsch, Bala Murali Krishna Mariserla, J. Matthew Kim, Keshav M. Dani, Hans A. Bechtel, Ernerst Arushanov, Mazhar Ali
Physics
We report ultrafast optical measurements of the Dirac line-node semimetal ZrSiS and the Weyl semimetal NbAs, using mid-infrared pump photons from 86 meV to 500 meV to directly excite Dirac and Weyl fermions within the linearly dispersing bands. In NbAs, the photoexcited Weyl fermions initially form a non-thermal distribution, signified by a brief spike in the differential reflectivity whose sign is controlled by the relative energy of the pump and probe photons. In ZrSiS, electron-electron scattering rapidly thermalizes the electrons, and the spike is not observed. Subsequently, hot carriers in both materials cool within a few picoseconds. This cooling, as …
Using Coherent Phonons For Ultrafast Control Of The Dirac Node Of Srmnsb2, Christopher P. Weber, Madison G. Masten, Thomas C. Ogloza, Bryan S. Berggren, Michael K. L. Man, Keshav M. Dani, Jinyu Liu, Zhiqiang Mao, Dennis D. Klug, Adebayo A. Adeleke, Yansun Yao
Using Coherent Phonons For Ultrafast Control Of The Dirac Node Of Srmnsb2, Christopher P. Weber, Madison G. Masten, Thomas C. Ogloza, Bryan S. Berggren, Michael K. L. Man, Keshav M. Dani, Jinyu Liu, Zhiqiang Mao, Dennis D. Klug, Adebayo A. Adeleke, Yansun Yao
Physics
SrMnSb2 is a candidate Dirac semimetal whose electrons near the Y point have the linear dispersion and low mass of a Dirac cone. Here we demonstrate that ultrafast, 800-nm optical pulses can launch coherent phonon oscillations in Sr0.94Mn0.92Sb2, particularly an Ag mode at 4.4 THz. Through first-principles calculations of the electronic and phononic structure of SrMnSb2, we show that high-amplitude oscillations of this mode would displace the atoms in a way that transiently opens and closes a gap at the node of the Dirac cone. The ability to control the …
Structural And Wetting Properties Of Nature's Finest Silks (Order Embioptera), Grace Y. Stokes, Evangelea N. Dicicco, Trevor J. Moore, Vivian C. Cheng, Kira Y. Wheeler, John Soghigian, Richard P. Barber Jr., Janice Edgerly-Rooks
Structural And Wetting Properties Of Nature's Finest Silks (Order Embioptera), Grace Y. Stokes, Evangelea N. Dicicco, Trevor J. Moore, Vivian C. Cheng, Kira Y. Wheeler, John Soghigian, Richard P. Barber Jr., Janice Edgerly-Rooks
Physics
Insects from the order Embioptera (webspinners) spin silk fibres which are less than 200 nm in diameter. In this work, we characterized and compared the diameters of single silk fibres from nine species—Antipaluria urichi, Pararhagadochir trinitatis, Saussurembia calypso, Diradius vandykei, Aposthonia ceylonica, Haploembia solieri, H. tarsalis, Oligotoma nigra and O. saundersii. Silk from seven of these species have not been previously quantified. Our studies cover five of the 10 named taxonomic families and represent about one third of the known taxonomic family-level diversity in the order Embioptera. Naturally spun silk varied …
Energy Loss Due To Defect Formation From 206Pb Recoils In Supercdms Germanium Detectors, R. Agnese, T. Aralis, T. Aramaki, I. J. Arnquist, E. Azadbakht, W. Baker, S. Banik, D. Barker, D. A. Bauer, T. Binder, M. A. Bowles, P. L. Brink, R. Bunker, B. Cabrera, R. Calkins, D. G. Cerdeno, Y.-Y. Chang, J. Cooley, B. Cornell, P. Cushman, P. C. F. Di Stefano, T. Doughty, E. Fascione, E. Figueroa-Feliciano, C. W. Fink, M. Fritts, G. Gerbier, R. Germond, M. Ghaith, S. R. Golwala, H. R. Harris, Z. Hong, E. W. Hoppe, L. Hsu, M. E. Huber, V. Iyer, D. Jardin, C. Jena, M. H. Kelsey, A. Kennedy, A. Kubik, N. A. Kurinsky, R. E. Lawrence, B. Loer, E. Lopez Asamar, P. Lukens, D. Macdonell, R. Mahapatra, V. Mandic, N. Mast, E. H. Miller, N. Mirabolfathi, B. Mohanty, J. D. Morales Mendoza, J. Nelson, J. L. Orrell, S. M. Oser, W. A. Page, R. Partridge, M. Pepin, F. Ponce, S. Poudel, M. Pyle, H. Qui, W. Rau, A. Reisetter, T. Ren, T. Reynolds, A. Roberts, A. E. Robinson, H. E. Rogers, T. Saab, B. Sadoulet, J. Sander, A. Scarff, R. W. Schnee, S. Scorza, K. Senapati, B. Serfass, D. Speller, M. Stein, J. Street, H. A. Tanaka, D. Toback, R. Underwood, A. N. Villano, B. Von Krosigk, S. L. Watkins, J. S. Wilson, M. J. Wilson, J. Winchell, D. H. Wright, S. Yellin, Betty A. Young, X. Zhang, X. Xhao
Energy Loss Due To Defect Formation From 206Pb Recoils In Supercdms Germanium Detectors, R. Agnese, T. Aralis, T. Aramaki, I. J. Arnquist, E. Azadbakht, W. Baker, S. Banik, D. Barker, D. A. Bauer, T. Binder, M. A. Bowles, P. L. Brink, R. Bunker, B. Cabrera, R. Calkins, D. G. Cerdeno, Y.-Y. Chang, J. Cooley, B. Cornell, P. Cushman, P. C. F. Di Stefano, T. Doughty, E. Fascione, E. Figueroa-Feliciano, C. W. Fink, M. Fritts, G. Gerbier, R. Germond, M. Ghaith, S. R. Golwala, H. R. Harris, Z. Hong, E. W. Hoppe, L. Hsu, M. E. Huber, V. Iyer, D. Jardin, C. Jena, M. H. Kelsey, A. Kennedy, A. Kubik, N. A. Kurinsky, R. E. Lawrence, B. Loer, E. Lopez Asamar, P. Lukens, D. Macdonell, R. Mahapatra, V. Mandic, N. Mast, E. H. Miller, N. Mirabolfathi, B. Mohanty, J. D. Morales Mendoza, J. Nelson, J. L. Orrell, S. M. Oser, W. A. Page, R. Partridge, M. Pepin, F. Ponce, S. Poudel, M. Pyle, H. Qui, W. Rau, A. Reisetter, T. Ren, T. Reynolds, A. Roberts, A. E. Robinson, H. E. Rogers, T. Saab, B. Sadoulet, J. Sander, A. Scarff, R. W. Schnee, S. Scorza, K. Senapati, B. Serfass, D. Speller, M. Stein, J. Street, H. A. Tanaka, D. Toback, R. Underwood, A. N. Villano, B. Von Krosigk, S. L. Watkins, J. S. Wilson, M. J. Wilson, J. Winchell, D. H. Wright, S. Yellin, Betty A. Young, X. Zhang, X. Xhao
Physics
The Super Cryogenic Dark Matter Search experiment (SuperCDMS) at the Soudan Underground Laboratory studied energy loss associated with Frenkel defect formation in germanium crystals at mK temperatures using in situ 210Pb sources. We examine the spectrum of 206Pb nuclear recoils near its expected 103 keV endpoint energy and determine an energy loss of (6.08±0.18) %, which we attribute to defect formation. From this result and using TRIM simulations, we extract the first experimentally determined average displacement threshold energy of (19.7+0.6−0.5) eV for germanium. This has implications for the analysis thresholds of future germanium-based dark matter …
First Dark Matter Constraints From A Supercdms Single-Charge Sensitive Detector, R. Agnese, T. Aralis, T. Aramaki, I. J. Arnquist, E. Azadbakht, W. Baker, S. Banik, D. Barker, S. Banik, D. Barker, D. A. Bauer, T. Binder, M. A. Bowles, P. L. Brink, R. Bunker, Blas Cabrera, R. Calkins, C. Cartaro, D. G. Cerdeño, Y. Y. Chang, J. Cooley, B. Cornell, P. Cushman, P. C. F. Di Stefano, T. Doughty, E. Fascione, E. Figueroa-Feliciano, C. Fink, M. Fritts, G. Gerbier, R. Germond, M. Ghaith, S. R. Golwala, H. R. Harris, Z. Hong, E. W. Hoppe, L. Hsu, M. E. Huber, V. Iyers, D. Jardin, C. Jena, M. H. Kelsey, A. Kennedy, A. Kubik, N. A. Kurinsky, R. E. Lawrence, J. V. Leyva, B. Loer, E. Lopez Asamar, P. Lukens, D. Macdonell, R. Mahapatra, V. Mandic, N. Mast, E. H. Miller, N. Mirabolfathi, B. Mohanty, J. D. Morales Mendoza, J. Nelson, J. L. Orrell, S. M. Oser, W. A. Page, R. Partridge, M. Pepin, A. Phipps, F. Ponce, S. Poudel, M. Pyle, H. Qui, W. Rau, A. Reisetter, T. Reynolds, A. Roberts, A. E. Robinson, H. E. Rogers, R. K. Romani, T. Saab, B. Sadoulet, J. Sander, A. Scarff, R. W. Schnee, S. Scorza, K. Senapati, B. Serfass, J. So, D. Speller, C. Stanford, M. Stein, J. Street, H. A. Tanaka, D. Toback, R. Underwood, A. N. Villano, B. Von Krosigk, S. L. Watkins, J. S. Wilson, M. J. Wilson, J. Winchell, D. H. Wright, S. Yellin, Betty A. Young, X. Zhang, X. Zhao
First Dark Matter Constraints From A Supercdms Single-Charge Sensitive Detector, R. Agnese, T. Aralis, T. Aramaki, I. J. Arnquist, E. Azadbakht, W. Baker, S. Banik, D. Barker, S. Banik, D. Barker, D. A. Bauer, T. Binder, M. A. Bowles, P. L. Brink, R. Bunker, Blas Cabrera, R. Calkins, C. Cartaro, D. G. Cerdeño, Y. Y. Chang, J. Cooley, B. Cornell, P. Cushman, P. C. F. Di Stefano, T. Doughty, E. Fascione, E. Figueroa-Feliciano, C. Fink, M. Fritts, G. Gerbier, R. Germond, M. Ghaith, S. R. Golwala, H. R. Harris, Z. Hong, E. W. Hoppe, L. Hsu, M. E. Huber, V. Iyers, D. Jardin, C. Jena, M. H. Kelsey, A. Kennedy, A. Kubik, N. A. Kurinsky, R. E. Lawrence, J. V. Leyva, B. Loer, E. Lopez Asamar, P. Lukens, D. Macdonell, R. Mahapatra, V. Mandic, N. Mast, E. H. Miller, N. Mirabolfathi, B. Mohanty, J. D. Morales Mendoza, J. Nelson, J. L. Orrell, S. M. Oser, W. A. Page, R. Partridge, M. Pepin, A. Phipps, F. Ponce, S. Poudel, M. Pyle, H. Qui, W. Rau, A. Reisetter, T. Reynolds, A. Roberts, A. E. Robinson, H. E. Rogers, R. K. Romani, T. Saab, B. Sadoulet, J. Sander, A. Scarff, R. W. Schnee, S. Scorza, K. Senapati, B. Serfass, J. So, D. Speller, C. Stanford, M. Stein, J. Street, H. A. Tanaka, D. Toback, R. Underwood, A. N. Villano, B. Von Krosigk, S. L. Watkins, J. S. Wilson, M. J. Wilson, J. Winchell, D. H. Wright, S. Yellin, Betty A. Young, X. Zhang, X. Zhao
Physics
We present the first limits on inelastic electron-scattering dark matter and dark photon absorption using a prototype SuperCDMS detector having a charge resolution of 0.1 electron-hole pairs (CDMS HVeV, a 0.93 gram CDMS HV device). These electron-recoil limits significantly improve experimental constraints on dark matter particles with masses as low as 1 MeV/c2. We demonstrate a sensitivity to dark photons competitive with other leading approaches but using substantially less exposure (0.49 gram days). These results demonstrate the scientific potential of phonon-mediated semiconductor detectors that are sensitive to single electronic excitations.
Time-Dependent Efficiency Measurements Of Polymer Solar Cells With Dye Additives: Unexpected Initial Increase Of Efficiency, Kyle J. Bandaccari, Grace E. Chesmore, Mitchel Bugaj, Parisa Tajalli-Tehrani Valverde, Richard P. Barber Jr., Brian J. Mcnelis
Time-Dependent Efficiency Measurements Of Polymer Solar Cells With Dye Additives: Unexpected Initial Increase Of Efficiency, Kyle J. Bandaccari, Grace E. Chesmore, Mitchel Bugaj, Parisa Tajalli-Tehrani Valverde, Richard P. Barber Jr., Brian J. Mcnelis
Physics
We report the effects of the addition of two azo-dye additives on the time-dependent efficiency of polymer solar cells. Although the maximum efficiencies of devices containing different amounts of dye do not vary greatly over the selected concentration range, the time dependence results reveal a surprising initial increase in efficiency in some samples. We observe this effect to be correlated with a leakage current, although a specific mechanism is not yet identified. We also present the measured lifetimes of these solar cells, and find that variations in dye concentrations produce a small effect at most. Characterization of the bulk heterojunction …
Results From The Super Cryogenic Dark Matter Search (Supercdms) Experiment At Soudan, R. Agnese, T. Aramaki, I. J. Arnquist, W. Baker, D. Balakishiyeva, S. Banik, D. Barker, R. Basu Thakur, D. A. Bauer, T. Binder, M. A. Bowles, P. L. Brink, R. Bunker, Blas Cabrera, D. O. Caldwell, R. Calkins, C. Cartaro, D. G. Cerdeño, Y. Chang, Y. Chen, J. Cooley, B. Cornell, P. Cushman, M. Daal, P. C. F. Di Stefano, T. Doughty, E. Fascione, E. Figueroa-Feliciano, M. Fritts, G. Gerbier, R. Germond, M. Ghaith, G. L. Godfrey, S. R. Golwala, J. Hall, H. R. Harris, Z. Hong, E. W. Hoppe, L. Hsu, M. E. Huber, V. Iyer, D. Jardin, A. Jastram, C. Jena, M. H. Kelsey, A. Kennedy, A. Kubik, N. A. Kurinsky, B. Loer, E. Lopez Asamar, P. Lukens, D. Macdonell, R. Mahapatra, V. Mandic, N. Mast, E. H. Miller, N. Page, W. A. Page, R. Partridge, M. Penalver Martinez, M. Pepin, A. Phipps, S. Poudel, M. Pyle, H. Qiu, W. Rau, P. Redl, A. Reisetter, T. Reynolds, A. Roberts, A. E. Robinson, H. E. Rogers, T. Saab, B. Sadoulet, J. Sander, K. Schneck, R. W. Schnee, S. Scorza, K. Senapati, B. Serfass, D. Speller, M. Stein, J. Street, H. A. Tanaka, D. Toback, R. Underwood, A. N. Villano, B. Von Krosigk, B. Welliver, J. S. Wilson, M. J. Wilson, D. H. Wright, S. Yellin, J. J. Yen, Betty A. Young, X. Zhang, X Zhao
Results From The Super Cryogenic Dark Matter Search (Supercdms) Experiment At Soudan, R. Agnese, T. Aramaki, I. J. Arnquist, W. Baker, D. Balakishiyeva, S. Banik, D. Barker, R. Basu Thakur, D. A. Bauer, T. Binder, M. A. Bowles, P. L. Brink, R. Bunker, Blas Cabrera, D. O. Caldwell, R. Calkins, C. Cartaro, D. G. Cerdeño, Y. Chang, Y. Chen, J. Cooley, B. Cornell, P. Cushman, M. Daal, P. C. F. Di Stefano, T. Doughty, E. Fascione, E. Figueroa-Feliciano, M. Fritts, G. Gerbier, R. Germond, M. Ghaith, G. L. Godfrey, S. R. Golwala, J. Hall, H. R. Harris, Z. Hong, E. W. Hoppe, L. Hsu, M. E. Huber, V. Iyer, D. Jardin, A. Jastram, C. Jena, M. H. Kelsey, A. Kennedy, A. Kubik, N. A. Kurinsky, B. Loer, E. Lopez Asamar, P. Lukens, D. Macdonell, R. Mahapatra, V. Mandic, N. Mast, E. H. Miller, N. Page, W. A. Page, R. Partridge, M. Penalver Martinez, M. Pepin, A. Phipps, S. Poudel, M. Pyle, H. Qiu, W. Rau, P. Redl, A. Reisetter, T. Reynolds, A. Roberts, A. E. Robinson, H. E. Rogers, T. Saab, B. Sadoulet, J. Sander, K. Schneck, R. W. Schnee, S. Scorza, K. Senapati, B. Serfass, D. Speller, M. Stein, J. Street, H. A. Tanaka, D. Toback, R. Underwood, A. N. Villano, B. Von Krosigk, B. Welliver, J. S. Wilson, M. J. Wilson, D. H. Wright, S. Yellin, J. J. Yen, Betty A. Young, X. Zhang, X Zhao
Physics
We report the result of a blinded search for Weakly Interacting Massive Particles (WIMPs) using the majority of the SuperCDMS Soudan dataset. With an exposure of 1690 kg days, a single candidate event is observed, consistent with expected backgrounds. This analysis (combined with previous Ge results) sets an upper limit on the spin-independent WIMP--nucleon cross section of 1.4×10−44 (1.0×10−44) cm2 at 46 GeV/c2. These results set the strongest limits for WIMP--germanium-nucleus interactions for masses >12 GeV/c2.
Thermal Detection Of Single E-H Pairs In A Biased Silicon Crystal Detector, R. K. Romani, P. L. Brink, Blas Cabrera, M. Cherry, T. Howarth, N. Kurinsky, R. A. Moffatt, R. Partiridge, F. Ponce, M. Pyle, A. Tomada, S. Yellin, J. J. Yen, Betty A. Young
Thermal Detection Of Single E-H Pairs In A Biased Silicon Crystal Detector, R. K. Romani, P. L. Brink, Blas Cabrera, M. Cherry, T. Howarth, N. Kurinsky, R. A. Moffatt, R. Partiridge, F. Ponce, M. Pyle, A. Tomada, S. Yellin, J. J. Yen, Betty A. Young
Physics
We demonstrate that individual electron-hole pairs are resolved in a 1 cm2 by 4 mm thick silicon crystal (0.93 g) operated at ∼35 mK. One side of the detector is patterned with two quasiparticle-trap-assisted electro-thermal-feedback transition edge sensor arrays held near ground potential. The other side contains a bias grid with 20% coverage. Bias potentials up to ±160 V were used in the work reported here. A fiber optic provides 650 nm (1.9 eV) photons that each produce an electron-hole (e– h+) pair in the crystal near the grid. The energy of the drifting charges is …
Low-Mass Dark Matter Search With Cdmslite, R. Agnese, A. J. Anderson, T. Aralis, T. Aramaki, I. J. Arnquist, W. Baker, D. Balakishiyeva, D. Barker, R. Basu Thakur, D. A. Bauer, T. Binder, M. A. Bowles, P. L. Brink, R. Bunker, Blas Cabrera, D. O. Caldwell, R. Calkins, C. Cartaro, D. G. Cerdeño, Y. Chang, H. Chagani, Y. Chen, J. Cooley, B. Cornell, P. Cushman, M. Daal, P.C. F. Di Stefano, T. Doughty, L. Esteban, E. Fascione, E. Figueroa-Feliciano, M. Fritts, G. Gerbier, M. Ghaith, G. L. Godfrey, S. R. Golwala, J. Hall, H. R. Harris, Z. Hong, E. W. Hoppe, L. Hsu, M. E. Huber, V. Iyer, D. Jardin, A. Jastram, C. Jena, M. H. Kelsey, A. Kennedy, A. Kubik, N. A. Kurinsky, A. Leder, B. Loer, E. Lopez Asamar, P. Lukens, D. Macdonell, R. Mahapatra, V. Mandic, N. Mast, E. H. Miller, N. Mirabolfathi, R. A. Moffatt, B. Mohanty, J. D. Morales Mendoza, J. Nelson, J. L. Orrell, S. M. Oser, K. Page, W. A. Page, R. Patridge, M. Pepin, M. Peñalver Martinez, A. Phipps, S. Poudel, M. Pyle, H. Qiu, W. Saab, B. Sadoulet, J. Sander, K. Schneck, R. W. Schnee, S. Scorza, K. Senapati, B. Serfass, D. Speller, M. Stein, J. Street, H. A. Tanaka, D. Toback, R. Underwood, A. N. Villano, B. Von Krosigk, B. Welliver, J. S. Wilson, M. J. Wilson, D. H. Wright, S. Yellin, J. J. Yen, Betty A. Young, X. Zhang, X. Zhao
Low-Mass Dark Matter Search With Cdmslite, R. Agnese, A. J. Anderson, T. Aralis, T. Aramaki, I. J. Arnquist, W. Baker, D. Balakishiyeva, D. Barker, R. Basu Thakur, D. A. Bauer, T. Binder, M. A. Bowles, P. L. Brink, R. Bunker, Blas Cabrera, D. O. Caldwell, R. Calkins, C. Cartaro, D. G. Cerdeño, Y. Chang, H. Chagani, Y. Chen, J. Cooley, B. Cornell, P. Cushman, M. Daal, P.C. F. Di Stefano, T. Doughty, L. Esteban, E. Fascione, E. Figueroa-Feliciano, M. Fritts, G. Gerbier, M. Ghaith, G. L. Godfrey, S. R. Golwala, J. Hall, H. R. Harris, Z. Hong, E. W. Hoppe, L. Hsu, M. E. Huber, V. Iyer, D. Jardin, A. Jastram, C. Jena, M. H. Kelsey, A. Kennedy, A. Kubik, N. A. Kurinsky, A. Leder, B. Loer, E. Lopez Asamar, P. Lukens, D. Macdonell, R. Mahapatra, V. Mandic, N. Mast, E. H. Miller, N. Mirabolfathi, R. A. Moffatt, B. Mohanty, J. D. Morales Mendoza, J. Nelson, J. L. Orrell, S. M. Oser, K. Page, W. A. Page, R. Patridge, M. Pepin, M. Peñalver Martinez, A. Phipps, S. Poudel, M. Pyle, H. Qiu, W. Saab, B. Sadoulet, J. Sander, K. Schneck, R. W. Schnee, S. Scorza, K. Senapati, B. Serfass, D. Speller, M. Stein, J. Street, H. A. Tanaka, D. Toback, R. Underwood, A. N. Villano, B. Von Krosigk, B. Welliver, J. S. Wilson, M. J. Wilson, D. H. Wright, S. Yellin, J. J. Yen, Betty A. Young, X. Zhang, X. Zhao
Physics
The SuperCDMS experiment is designed to directly detect weakly interacting massive particles (WIMPs) that may constitute the dark matter in our Galaxy. During its operation at the Soudan Underground Laboratory, germanium detectors were run in the CDMSlite mode to gather data sets with sensitivity specifically for WIMPs with masses /c2. In this mode, a higher detector-bias voltage is applied to amplify the phonon signals produced by drifting charges. This paper presents studies of the experimental noise and its effect on the achievable energy threshold, which is demonstrated to be as low as 56 eVee (electron equivalent energy). …
Similar Ultrafast Dynamics Of Several Dissimilar Dirac And Weyl Semimetals, Christopher P. Weber, Bryan S. Berggren, Madison G. Masten, Thomas C. Ogloza, Skylar Deckoff-Jones, Julien Madéo, Michael K. L. Man, Keshav M. Dani, Lingxiao Zhao, Genfu Chen, Jinyu Liu, Zhiqiang Mao, Leslie M. Schoop, Bettina V. Lotsch, Stuart S. P. Parkin, Mazhar Ali
Similar Ultrafast Dynamics Of Several Dissimilar Dirac And Weyl Semimetals, Christopher P. Weber, Bryan S. Berggren, Madison G. Masten, Thomas C. Ogloza, Skylar Deckoff-Jones, Julien Madéo, Michael K. L. Man, Keshav M. Dani, Lingxiao Zhao, Genfu Chen, Jinyu Liu, Zhiqiang Mao, Leslie M. Schoop, Bettina V. Lotsch, Stuart S. P. Parkin, Mazhar Ali
Physics
Recent years have seen the rapid discovery of solids whose low-energy electrons have a massless, linear dispersion, such as Weyl, line-node, and Dirac semimetals. The remarkable optical properties predicted in these materials show their versatile potential for optoelectronic uses. However, little is known of their response in the picoseconds after absorbing a photon. Here, we measure the ultrafast dynamics of four materials that share non-trivial band structure topology but that differ chemically, structurally, and in their low-energy band structures: ZrSiS, which hosts a Dirac line node and Dirac points; TaAs and NbP, which are Weyl semimetals; and Sr1–y …
L-Edge Spectroscopy Of Dilute, Radiation-Sensitive Systems Using A Transition-Edge-Sensor Array, Charles J. Titus, Michael L. Baker, Sang Jun Lee, Hsiao-Mei Cho, William B. Doriese, Joseph W. Fowler, Kelly Gaffney, Johnathon D. Gard, Gene C. Hilton, Chris Kenney, Jason Knight, Dale Li, Ronald Marks, Michael P. Minitti, Kelsey M. Morgan, Galen C. O'Neil, Carl D. Reintsema, Daniel R. Schmidt, Dimosthenis Sokaras, Daniel S. Swetz, Joel N. Ullom, Tsu-Chien Weng, Christopher Williams, Betty A. Young, Kent D. Irwin, Edward I. Solomon, Dennis Nordlund
L-Edge Spectroscopy Of Dilute, Radiation-Sensitive Systems Using A Transition-Edge-Sensor Array, Charles J. Titus, Michael L. Baker, Sang Jun Lee, Hsiao-Mei Cho, William B. Doriese, Joseph W. Fowler, Kelly Gaffney, Johnathon D. Gard, Gene C. Hilton, Chris Kenney, Jason Knight, Dale Li, Ronald Marks, Michael P. Minitti, Kelsey M. Morgan, Galen C. O'Neil, Carl D. Reintsema, Daniel R. Schmidt, Dimosthenis Sokaras, Daniel S. Swetz, Joel N. Ullom, Tsu-Chien Weng, Christopher Williams, Betty A. Young, Kent D. Irwin, Edward I. Solomon, Dennis Nordlund
Physics
We present X-ray absorption spectroscopy and resonant inelastic X-ray scattering (RIXS) measurements on the iron L-edge of 0.5 mM aqueous ferricyanide. These measurements demonstrate the ability of high-throughput transition-edge-sensor (TES) spectrometers to access the rich soft X-ray (100–2000 eV) spectroscopy regime for dilute and radiation-sensitive samples. Our low-concentration data are in agreement with high-concentration measurements recorded by grating spectrometers. These results show that soft-X-ray RIXS spectroscopy acquired by high-throughput TES spectrometers can be used to study the local electronic structure of dilute metal-centered complexes relevant to biology, chemistry, and catalysis. In particular, TES spectrometers have a unique ability to characterize …
Ambipolar Spin Diffusion In P-Type Gaas: A Case Where Spin Diffuses More Than Charge, F. Cadiz, V. Notot, J. Filipovic, Christopher P. Weber, L. Martinelli, A.C. H. Rowe, S. Arscott
Ambipolar Spin Diffusion In P-Type Gaas: A Case Where Spin Diffuses More Than Charge, F. Cadiz, V. Notot, J. Filipovic, Christopher P. Weber, L. Martinelli, A.C. H. Rowe, S. Arscott
Physics
We investigate the diffusion of charge and spin at 15 K in p-type GaAs, combining transient-grating and energy-resolved microluminescence measurements to cover a broad range of photoelectron density. At very low optical power, in a unipolar nondegenerate regime, charge and spin diffuse at the same rate, implying that the spin-drag effects are negligible. Upon increasing the photoelectron concentration up to about 1016 cm–3, the charge diffusion constant decreases because of ambipolar electrostatic interactions with the slower-diffusing holes while the spin diffusion constant is reduced only weakly by the ambipolar interaction. A further increase in the excitation power causes increases in …
Projected Sensitivity Of The Supercdms Snolab Experiment, R. Agnese, A. J. Anderson, T. Aramaki, I. J. Arnquist, W. Baker, D. Barker, R. Basu Thakur, D. A. Bauer, A. Borgland, M. A. Bowles, P. L. Brink, R. Bunker, Blas Cabrera, D. O. Caldwell, R. Calkins, C. Cartaro, D. G. Cerdeño, H. Chagani, Y. Chen, J. Cooley, B. Cornell, P. Cushman, M. Daal, P.C. F. Di Stefano, T. Doughty, L. Esteban, S. Fallows, E. Figueroa-Feliciano, M. Fritts, G. Gerbier, M. Ghaith, G. L. Godfrey, S. R. Golwala, J. Hall, H. R. Harris, T. Hofer, D. Holmgren, Z. Hong, E. Hoppe, L. Hsu, M. E. Huber, V. Iyer, D. Jardin, A. Jastram, M. H. Kelsey, A. Kennedy, A. Kubik, N. A. Kurinsky, A. Leder, B. Loer, E. Lopez Asamar, P. Lukens, R. Mahapatra, V. Mandic, N. Mast, N. Mirabolfathi, R. A. Moffatt, J. D. Morales Mendoza, J. L. Orrell, S. M. Oser, K. Page, W. A. Page, R. Partridge, M. Pepin, A. Phipps, S. Poudel, M. Pyle, H. Qiu, W. Rau, P. Redl, A. Reisetter, A. Roberts, A. E. Robinson, H. E. Rogers, T. Saab, B. Sadoulet, J. Sander, K. Schneck, R. W. Schnee, B. Serfass, D. Speller, M. Stein, J. Street, H. A. Tanaka, D. Toback, R. Underwood, A. N. Villano, B. Von Krosigk, B. Welliver, J. S. Wilson, D. H. Wright, S. Yellin, J. J. Yen, Betty A. Young, X. Zhang, X. Zhao
Projected Sensitivity Of The Supercdms Snolab Experiment, R. Agnese, A. J. Anderson, T. Aramaki, I. J. Arnquist, W. Baker, D. Barker, R. Basu Thakur, D. A. Bauer, A. Borgland, M. A. Bowles, P. L. Brink, R. Bunker, Blas Cabrera, D. O. Caldwell, R. Calkins, C. Cartaro, D. G. Cerdeño, H. Chagani, Y. Chen, J. Cooley, B. Cornell, P. Cushman, M. Daal, P.C. F. Di Stefano, T. Doughty, L. Esteban, S. Fallows, E. Figueroa-Feliciano, M. Fritts, G. Gerbier, M. Ghaith, G. L. Godfrey, S. R. Golwala, J. Hall, H. R. Harris, T. Hofer, D. Holmgren, Z. Hong, E. Hoppe, L. Hsu, M. E. Huber, V. Iyer, D. Jardin, A. Jastram, M. H. Kelsey, A. Kennedy, A. Kubik, N. A. Kurinsky, A. Leder, B. Loer, E. Lopez Asamar, P. Lukens, R. Mahapatra, V. Mandic, N. Mast, N. Mirabolfathi, R. A. Moffatt, J. D. Morales Mendoza, J. L. Orrell, S. M. Oser, K. Page, W. A. Page, R. Partridge, M. Pepin, A. Phipps, S. Poudel, M. Pyle, H. Qiu, W. Rau, P. Redl, A. Reisetter, A. Roberts, A. E. Robinson, H. E. Rogers, T. Saab, B. Sadoulet, J. Sander, K. Schneck, R. W. Schnee, B. Serfass, D. Speller, M. Stein, J. Street, H. A. Tanaka, D. Toback, R. Underwood, A. N. Villano, B. Von Krosigk, B. Welliver, J. S. Wilson, D. H. Wright, S. Yellin, J. J. Yen, Betty A. Young, X. Zhang, X. Zhao
Physics
SuperCDMS SNOLAB will be a next-generation experiment aimed at directly detecting low-mass (< 10 GeV/c2) particles that may constitute dark matter by using cryogenic detectors of two types (HV and iZIP) and two target materials (germanium and silicon). The experiment is being designed with an initial sensitivity to nuclear recoil cross sections ~ 1 x 10−43 cm2 for a dark matter particle mass of 1 GeV/c2, and with capacity to continue exploration to both smaller masses and better sensitivities. The phonon sensitivity of the HV detectors will be sufficient to detect nuclear recoils from sub-GeV dark …
Room-Temperature Self-Powered Energy Photodetector Based On Optically Induced Seebeck Effect In Cd3As2, Niloufar Yavarishad, Tahereh Hosseini, Elaheh Kheirandish, Christopher P. Weber, Nikolai Kouklin
Room-Temperature Self-Powered Energy Photodetector Based On Optically Induced Seebeck Effect In Cd3As2, Niloufar Yavarishad, Tahereh Hosseini, Elaheh Kheirandish, Christopher P. Weber, Nikolai Kouklin
Physics
We demonstrate an intrinsically fast Seebeck-type metal–semimetal–metal infrared photodetector based on Cd3As2 crystals. The Seebeck voltage is induced under off-center illumination, leading to asymmetric temperature gradients and a net current flow. The room-temperature responsivity of the sensor is 0.27 mA/W. The photocurrent signal is readily registered at a modulation frequency of 6 kHz, and the intrinsic bandwidth of the sensor is predicted to approach the terahertz range. The photocurrent depends on the optical power and modulation frequency. Our study demonstrates that crystallineCd3As2 is a promising material for high-bandwidth and spectrally broad photosensing, imaging, and …
Structure–Function Relationships Of Fullerene Esters In Polymer Solar Cells: Unexpected Structural Effects On Lifetime And Efficiency, Michael Tro, Alexis Sarabia, Kyle J. Bandaccari, David Oparko, Emma Lewis, Maxwell J. Giammona, Justin Isaac, Parisa Tajalli-Tehrani Valverde, Grace E. Chesmore, Thorsteinn Adalsteinsson, Richard P. Barber Jr., Brian J. Mcnelis
Structure–Function Relationships Of Fullerene Esters In Polymer Solar Cells: Unexpected Structural Effects On Lifetime And Efficiency, Michael Tro, Alexis Sarabia, Kyle J. Bandaccari, David Oparko, Emma Lewis, Maxwell J. Giammona, Justin Isaac, Parisa Tajalli-Tehrani Valverde, Grace E. Chesmore, Thorsteinn Adalsteinsson, Richard P. Barber Jr., Brian J. Mcnelis
Physics
We report both transport measurements and spectroscopic data of polymer/fullerene blend photovoltaics using a small library of fullerene esters to correlate device properties with a range of functionality and structural diversity of the ester substituent. We observe that minor structural changes can lead to significant and surprising differences in device efficiency and lifetime. For example we have found that isomeric R-groups in the fullerene ester-based devices we have studied have dramatically different efficiencies. The characteristic lifetimes derived from both transport and spectroscopic measurements are generally comparable; however, some more rapid effects in specific fullerene esters are not observed spectroscopically. It …
Imaging The Oblique Propagation Of Electrons In Germanium Crystals At Low Temperature And Low Electric Field, R. A. Moffatt, Blas Cabrera, B. M. Corcoran, J. M. Kreikebaum, P. Redl, B. Shank, J. J. Yen, Betty A. Young, P. L. Brink, M. Cherry, A. Tomada, A. Phipps, B. Sadoulet, K. M. Sundqvist
Imaging The Oblique Propagation Of Electrons In Germanium Crystals At Low Temperature And Low Electric Field, R. A. Moffatt, Blas Cabrera, B. M. Corcoran, J. M. Kreikebaum, P. Redl, B. Shank, J. J. Yen, Betty A. Young, P. L. Brink, M. Cherry, A. Tomada, A. Phipps, B. Sadoulet, K. M. Sundqvist
Physics
Excited electrons in the conduction band of germanium collect into four energy minima, or valleys, in momentum space. These local minima have highly anisotropic mass tensors which cause the electrons to travel in directions which are oblique to an applied electric field at sub-Kelvin temperatures and low electric fields, in contrast to the more isotropic behavior of the holes. This experiment produces a full two-dimensional image of the oblique electron and hole propagation and the quantum transitions of electrons between valleys for electric fields oriented along the [0,0,1] direction. Charge carriers are excited with a focused laser pulse on one …
Transient Reflectance Of Photoexcited Cd3As2, Christopher P. Weber, Ernest Arushanov, Bryan S. Berggren, Tahereh Hosseini, Nikolai Kouklin, Alex Nateprov
Transient Reflectance Of Photoexcited Cd3As2, Christopher P. Weber, Ernest Arushanov, Bryan S. Berggren, Tahereh Hosseini, Nikolai Kouklin, Alex Nateprov
Physics
We report ultrafast transient-grating measurements of crystals of the three-dimensional Dirac semimetal cadmium arsenide, Cd3As2, at both room temperature and 80 K. After photoexcitation with 1.5-eV photons, charge-carriers relax by two processes, one of duration 500 fs and the other of duration 3.1 ps. By measuring the complex phase of the change in reflectance, we determine that the faster signal corresponds to a decrease in absorption, and the slower signal to a decrease in the light's phase velocity, at the probe energy. We attribute these signals to electrons' filling of phase space, first near the photon …
Confocal Sputtering Of Conformal Α-Β Phase W Films On Etched Al Features, John Mark Kreikebaum, Blas Cabrera, Jeffrey J. Yen, Paul L. Brink, Matt Cherry, Astrid Tomada, Betty A. Young
Confocal Sputtering Of Conformal Α-Β Phase W Films On Etched Al Features, John Mark Kreikebaum, Blas Cabrera, Jeffrey J. Yen, Paul L. Brink, Matt Cherry, Astrid Tomada, Betty A. Young
Physics
The authors report on thin-film processing improvements in the fabrication of superconducting quasiparticle-trap-assisted electrothermal-feedback transition-edge sensors used in the design of cryogenic dark matter search detectors. The work was performed as part of a detector upgrade project that included optimization of a new confocal sputtering system and development of etch recipes compatible with patterning 40 nm-thick, α-β mixed-phase W films deposited on 300–600 nm-thick, patterned Al. The authors found that their standard exothermic Al wet etch recipes provided inadequate W/Al interfaces and led to poor device performance. The authors developed a modified Al wet-etch recipe that effectively mitigates geometrical step-coverage …
Nonlinear Optimal Filter Technique For Analyzing Energy Depositions In Tes Sensors Driven Into Saturation, B. Shank, J. J. Yen, Blas Cabrera, J. M. Kreikebaum, R. Moffatt, P. Redl, Betty A. Young, P. L. Brink, M. Cherry, A. Tomada
Nonlinear Optimal Filter Technique For Analyzing Energy Depositions In Tes Sensors Driven Into Saturation, B. Shank, J. J. Yen, Blas Cabrera, J. M. Kreikebaum, R. Moffatt, P. Redl, Betty A. Young, P. L. Brink, M. Cherry, A. Tomada
Physics
We present a detailed thermal and electrical model of superconducting transition edge sensors (TESs) connected to quasiparticle (qp) traps, such as the W TESs connected to Al qp traps used for CDMS (Cryogenic Dark Matter Search) Ge and Si detectors. We show that this improved model, together with a straightforward time-domain optimal filter, can be used to analyze pulses well into the nonlinear saturation region and reconstruct absorbed energies with optimal energy resolution.
Measurement Of Quasiparticle Transport In Aluminum Films Using Tungsten Transition-Edge Sensors, J. J. Yen, B. Shank, Betty A. Young, Blas Cabrera, P. L. Brink, M. Cherry, J. M. Kreikebaum, R. Moffatt, P. Redl, A. Tomada, E. C. Tortorici
Measurement Of Quasiparticle Transport In Aluminum Films Using Tungsten Transition-Edge Sensors, J. J. Yen, B. Shank, Betty A. Young, Blas Cabrera, P. L. Brink, M. Cherry, J. M. Kreikebaum, R. Moffatt, P. Redl, A. Tomada, E. C. Tortorici
Physics
We report on experimental studies of phonon sensors which utilize quasiparticle diffusion in thin aluminum films connected to tungsten transition-edge-sensors (TESs) operated at 35 mK. We show that basic TES physics and a simple physical model of the overlap region between the W and Al films in our devices enables us to accurately reproduce the experimentally observed pulse shapes from x-rays absorbed in the Al films. We further estimate quasiparticle loss in Al films using a simple diffusion equation approach. These studies allow the design of phonon sensors with improved performance.
Resistance And Lifetime Measurements Of Polymer Solar Cells Using Glycerol Doped Poly[3,4-Ethylenedioxythiophene]: Poly[Styrenesulfonate] Hole Injection Layers, Bhaskar Mantha, Emma Lewis, Richard P. Barber Jr.
Resistance And Lifetime Measurements Of Polymer Solar Cells Using Glycerol Doped Poly[3,4-Ethylenedioxythiophene]: Poly[Styrenesulfonate] Hole Injection Layers, Bhaskar Mantha, Emma Lewis, Richard P. Barber Jr.
Physics
We have performed resistivity measurements of poly[3,4-ethylenedioxythiophene]: poly[styrenesulfonate] (PEDOT:PSS) films with varying concentrations of glycerol. Resistivity is seen to decrease exponentially from roughly 3 Ω-cm for pure PEDOT:PSS to 3 × 10-2Ω-cm for 35 mg/cm3 glycerol in PEDOT:PSS. Beyond this concentration adding glycerol does not significantly change resistivity. Bulk heterojunction polymer solar cells using these variously doped PEDOT:PSS layers as electrodes were studied to characterize the effects on efficiency and lifetime. Although our data display significant scatter, lowering the resistance of the PEDOT:PSS layers results in lower device resistance and higher efficiency as expected. We also note that the lifetime …
Rapid Diffusion Of Electrons In Gamnas, Christopher P. Weber, Eric A. Kittlaus, Kassandra B. Mattia, Christopher J. Waight, J. Hagmann, X. Liu, M. Dobrowolska, J. K. Furdyna
Rapid Diffusion Of Electrons In Gamnas, Christopher P. Weber, Eric A. Kittlaus, Kassandra B. Mattia, Christopher J. Waight, J. Hagmann, X. Liu, M. Dobrowolska, J. K. Furdyna
Physics
We report ultrafast transient‐grating measurements, above and below the Curie temperature, of the dilute ferromagnetic semiconductor (Ga,Mn)As containing 6% Mn. At 80 K (15 K), we observe that photoexcited electrons in the conduction band have a lifetime of 8 ps (5 ps) and diffuse at about 70 cm2/s (60 cm2/s). Such rapid diffusion requires either an electronic mobility exceeding 7700 cm2/V s or a conduction‐band effective mass less than half the GaAs value. Our data suggest that neither the scattering rate nor the effective mass of the (Ga,Mn)As conduction band differs significantly from that …
Diffusion Of Degenerate Minority Carrier In A P-Type Semiconductor, Christopher P. Weber, Eric A. Kittlaus
Diffusion Of Degenerate Minority Carrier In A P-Type Semiconductor, Christopher P. Weber, Eric A. Kittlaus
Physics
We report ultrafast transient-grating experiments on heavily p-type InP at 15 K. Our measurement reveals the dynamics and diffusion of photoexcited electrons and holes as a function of their density n in the range 2 × 1016 to 6 × 1017 cm−3. After the first few picoseconds, the grating decays primarily due to ambipolar diffusion. While, at low density, we observe a regime in which the ambipolar diffusion is electron-dominated and increases rapidly with n, it appears to saturate at 34 cm2/s at high n. We present a simple calculation that reproduces the main …
Transport And Spectroscopic Studies Of The Effects Of Fullerene Structure On The Efficiency And Lifetime Of Polythiophene-Based Solar Cells, Emilee L. Sena, Justin H. Peel, Devin Wesenberg, Shreya Nathan, Marianne Wallis, Maxwell J. Giammona, Thorsteinn Adalsteinsson, Brian J. Mcnelis, Richard P. Barber Jr.
Transport And Spectroscopic Studies Of The Effects Of Fullerene Structure On The Efficiency And Lifetime Of Polythiophene-Based Solar Cells, Emilee L. Sena, Justin H. Peel, Devin Wesenberg, Shreya Nathan, Marianne Wallis, Maxwell J. Giammona, Thorsteinn Adalsteinsson, Brian J. Mcnelis, Richard P. Barber Jr.
Physics
Time-dependent measurements of both power conversion efficiency and ultraviolet-visible absorption spectroscopy have been observed for solar cell blends containing the polymer poly(3-hexylthiophene-2,5-diyl) (P3HT) with two different functionalized C60 electron acceptor molecules: commercially available [6,6]-phenyl C61 butyric acid methyl ester (PCBM) or [6,6]-phenyl C61 butyric acid octadecyl ester (PCBOD) produced in this laboratory. Efficiency was found to decay with an exponential time dependence, while spectroscopic features show saturating exponential behavior. Time constants extracted from both types of measurements showed reasonable agreement for samples produced from the same blend. In comparison to the PCBM samples, the stability of the PCBOD blends was …
Measurement Of Spin Diffusion In Semi-Insulating Gaas, Christopher P. Weber, Craig A. Benko, Stanley C. Hiew
Measurement Of Spin Diffusion In Semi-Insulating Gaas, Christopher P. Weber, Craig A. Benko, Stanley C. Hiew
Physics
We use optical transient-grating spectroscopy to measure the spin diffusion of optically oriented electrons in bulk, semi-insulating GaAs(100). Trapping and recombination do not quickly deplete the photoexcited population. The spin diffusion coefficient of 88±12 cm2/s is roughly constant at temperatures from 15 K to 150 K, and the spin diffusion length is at least 450 nm. We show that it is possible to use spin diffusion to estimate the electron diffusion coefficient. Due to electron-electron interactions, the electron diffusion is 1.4 times larger than the spin diffusion.
Electronic Structure Of Warm Dense Copper Studied By Ultrafast X-Ray Absorption Spectroscopy, B. I. Cho, K. Engelhorn, A. A. Correa, T. Ogitsu, Christopher P. Weber, H. J. Lee, J. Feng, P. A. Ni, Y. Ping, A. J. Nelson, D. Prendergast, R. W. Lee, R. W. Falcone, P. A. Heimann
Electronic Structure Of Warm Dense Copper Studied By Ultrafast X-Ray Absorption Spectroscopy, B. I. Cho, K. Engelhorn, A. A. Correa, T. Ogitsu, Christopher P. Weber, H. J. Lee, J. Feng, P. A. Ni, Y. Ping, A. J. Nelson, D. Prendergast, R. W. Lee, R. W. Falcone, P. A. Heimann
Physics
We use time-resolved x-ray absorption spectroscopy to investigate the unoccupied electronic density of states of warm dense copper that is produced isochorically through the absorption of an ultrafast optical pulse. The temperature of the superheated electron-hole plasma, which ranges from 4000 to 10 000 K, was determined by comparing the measured x-ray absorption spectrum with a simulation. The electronic structure of warm dense copper is adequately described with the high temperature electronic density of state calculated by the density functional theory. The dynamics of the electron temperature is consistent with a two-temperature model, while a temperature-dependent electron-phonon coupling parameter is …