Open Access. Powered by Scholars. Published by Universities.®
- Keyword
-
- Ultrafast electron diffraction (6)
- Electron (4)
- Quantum electrodynamics (4)
- Spin crossover (4)
- Ultrafast (4)
-
- Ferroelectricity (3)
- Magnetic nanoparticles (3)
- Physics (3)
- Self-assembly (3)
- Stochastic electrodynamics (3)
- Au(111) (2)
- Cluster deposition (2)
- Cold atoms (2)
- Computer programs (2)
- Density functional theory (2)
- Diffraction (2)
- Electron beams (2)
- Fragmentation (2)
- Gas electron diffraction (2)
- Harmonic oscillator (2)
- Heusler compounds (2)
- High-order harmonic generation (2)
- In Se 4 3 (2)
- Ionization (2)
- Kapitza-Dirac effect (2)
- Laser (2)
- Light (2)
- Molecular electronics (2)
- Molecular spintronics (2)
- Parametric excitation (2)
- Publication Year
- Publication
-
- Nebraska Center for Materials and Nanoscience: Faculty Publications (59)
- Anthony F. Starace Publications (43)
- Xiaoshan Xu Papers (32)
- Robert Streubel Papers (31)
- Peter Dowben Publications (30)
-
- Martin Centurion Publications (25)
- Xia Hong Publications (21)
- Stephen Ducharme Publications (20)
- Timothy J. Gay Publications (19)
- Department of Physics and Astronomy: Faculty Publications (16)
- Paul Burrow Publications (16)
- Department of Physics and Astronomy: Dissertations, Theses, and Student Research (15)
- Alexei Gruverman Publications (11)
- Kirill Belashchenko Publications (10)
- Donald Umstadter Publications (8)
- Kenneth Bloom Publications (4)
- Honors Theses (3)
- Matthias Fuchs Publications (3)
- UCARE Research Products (3)
- C.J.G.J. Uiterwaal Publications (2)
- Library Philosophy and Practice (e-journal) (2)
- Christian Binek Publications (1)
- David Sellmyer Publications (1)
- Department of Electrical and Computer Engineering: Faculty Publications (1)
- Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research (1)
- Herman Batelaan Publications (1)
- M. Eugene Rudd Publications (1)
- Papers from the University Studies series (University of Nebraska) (1)
- Ralph Skomski Publications (1)
- Robert Katz Publications (1)
Articles 31 - 60 of 384
Full-Text Articles in Physics
Correction To "Quantitative Study Of The Energy Changes In Voltage-Controlled Spin Crossover Molecular Thin Films" [The Journal Of Physical Chemistry Letters (2020) 11:19 (8231-8237) Doi: 10.1021/Acs.Jpclett.0c02209], Aaron Mosey, Ashley S. Dale, Guanhua Hao, Alpha N'Diaye, Peter Dowben, Ruihua Cheng
Correction To "Quantitative Study Of The Energy Changes In Voltage-Controlled Spin Crossover Molecular Thin Films" [The Journal Of Physical Chemistry Letters (2020) 11:19 (8231-8237) Doi: 10.1021/Acs.Jpclett.0c02209], Aaron Mosey, Ashley S. Dale, Guanhua Hao, Alpha N'Diaye, Peter Dowben, Ruihua Cheng
Peter Dowben Publications
In our recent publication, Figure 5 was published without adequate due diligence. The correct TOC Abstract graphic and Figure 5 are contained here in this correction. The correct on to off current ratios are in the range of 4 to 5, not 100 and the signal to noise ratios are far less than previously shown.
Electron Beam Dispersion Compensator Using A Wien Filter, Jackson Lederer
Electron Beam Dispersion Compensator Using A Wien Filter, Jackson Lederer
Honors Theses
When an electron beam travels through space, it spreads out over time which impedes the ability to work with short electron pulses in the lab. A Wien filter is a device consisting of perpendicular electric and magnetic fields which filters charged particles based on their velocities. For a specific velocity, the two forces from the two fields in the filter cancel each other out letting charges with that velocity travel straight through the filter. Charges moving at other speeds are deflected as they have a net force applied to them from the filter. If a particle is deflected from the …
Nonvolatile Voltage Controlled Molecular Spin‐State Switching For Memory Applications, Thilini K. Ekanayaka, Guanhua Hao, Aaron Mosey, Ashley S. Dale, Xuanyuan Jiang, Andrew J. Yost, Keshab R. Sapkota, George T. Wang, Jian Zhang, Alpha T. N’Diaye, Andrew Marshall, Ruihua Cheng, Azad Naeemi, Xiaoshan Xu, Peter Dowben
Nonvolatile Voltage Controlled Molecular Spin‐State Switching For Memory Applications, Thilini K. Ekanayaka, Guanhua Hao, Aaron Mosey, Ashley S. Dale, Xuanyuan Jiang, Andrew J. Yost, Keshab R. Sapkota, George T. Wang, Jian Zhang, Alpha T. N’Diaye, Andrew Marshall, Ruihua Cheng, Azad Naeemi, Xiaoshan Xu, Peter Dowben
Peter Dowben Publications
Nonvolatile, molecular multiferroic devices have now been demonstrated, but it is worth giving some consideration to the issue of whether such devices could be a competitive alternative for solid-state nonvolatile memory. For the Fe (II) spin crossover complex [Fe{H2B(pz)2}2(bipy)], where pz = tris(pyrazol-1-yl)-borohydride and bipy = 2,20-bipyridine, voltage-controlled isothermal changes in the electronic structure and spin state have been demonstrated and are accompanied by changes in conductance. Higher conductance is seen with [Fe{H2B(pz)2}2(bipy)] in the high spin state, while lower conductance occurs for the low spin state. Plausibly, …
Remote Mesoscopic Signatures Of Induced Magnetic Texture In Graphene, N. Arabchigavkani, R. Somphonsane, H. Ramamoorthy, G. He, J. Nathawat, S. Yin, B. Barut, K. He, M. D. Randle, R. Dixit, K. Sakanashi, N. Aoki, K. Zhang, L. Wang, W. N. Mei, Peter Dowben, J. Fransson, J. P. Bird
Remote Mesoscopic Signatures Of Induced Magnetic Texture In Graphene, N. Arabchigavkani, R. Somphonsane, H. Ramamoorthy, G. He, J. Nathawat, S. Yin, B. Barut, K. He, M. D. Randle, R. Dixit, K. Sakanashi, N. Aoki, K. Zhang, L. Wang, W. N. Mei, Peter Dowben, J. Fransson, J. P. Bird
Peter Dowben Publications
Mesoscopic conductance fluctuations are a ubiquitous signature of phase-coherent transport in small conductors, exhibiting universal character independent of system details. In this Letter, however, we demonstrate a pronounced breakdown of this universality, due to the interplay of local and remote phenomena in transport. Our experiments are performed in a graphene-based interaction-detection geometry, in which an artificial magnetic texture is induced in the graphene layer by covering a portion of it with a micromagnet. When probing conduction at some distance from this region, the strong influence of remote factors is manifested through the appearance of giant conductance fluctuations, with amplitude much …
Plasmonic Waveguides To Enhance Quantum Electrodynamic Phenomena At The Nanoscale, Ying Li, Christos Argyropoulos
Plasmonic Waveguides To Enhance Quantum Electrodynamic Phenomena At The Nanoscale, Ying Li, Christos Argyropoulos
Department of Electrical and Computer Engineering: Faculty Publications
The emerging field of plasmonics can lead to enhanced light-matter interactions at extremely nanoscale regions. Plasmonic (metallic) devices promise to efficiently control both classical and quantum properties of light. Plasmonic waveguides are usually used to excite confined electromagnetic modes at the nanoscale that can strongly interact with matter. The analysis of these nanowaveguides exhibits similarities with their low frequency microwave counterparts. In this article, we review ways to study plasmonic nanostructures coupled to quantum optical emitters from a classical electromagnetic perspective. These quantum emitters are mainly used to generate single-photon quantum light that can be employed as a quantum bit …
Chiral Spin Textures In Amorphous Iron–Germanium Thick Films, Robert Streubel, D. Simca Bouma, Frank Bruni, Xiaoqian Chen, Peter Ercius, Jim Ciston, Alpha T. N'Diaye, Sujoy Roy, Steve D. Kevan, Peter Fischer, Frances Hellman
Chiral Spin Textures In Amorphous Iron–Germanium Thick Films, Robert Streubel, D. Simca Bouma, Frank Bruni, Xiaoqian Chen, Peter Ercius, Jim Ciston, Alpha T. N'Diaye, Sujoy Roy, Steve D. Kevan, Peter Fischer, Frances Hellman
Robert Streubel Papers
Topological solitary fields, such as magnetic and polar skyrmions, are envisioned to revolutionize microelectronics. These configurations have been stabilized in solid-state materials with a global inversion symmetry breaking, which translates in magnetic materials into a vector spin exchange known as the Dzyaloshinskii–Moriya interaction (DMI), as well as spin chirality selection and isotropic solitons. This work reports experimental evidence of 3D chiral spin textures, such as helical spins and skyrmions with different chirality and topological charge, stabilized in amorphous Fe–Ge thick films. These results demonstrate that structurally and chemically disordered materials with a random DMI can resemble inversion symmetry broken systems …
Structure Retrieval In Liquid-Phase Electron Scattering, Jie Yang, J. Pedro F. Nunes, Kathryn Ledbetter, Elisa Biasin, Martin Centurion, Zhijiang Chen, Amy A. Cordones, Christopher Crissman, Daniel P. Deponte, Siegfried H. Glenzer, Ming Fu Lin, Mianzhen Mo, Conor D. Rankine, Xiaozhe Shen, Thomas J.A. Wolf, Xijie Wang
Structure Retrieval In Liquid-Phase Electron Scattering, Jie Yang, J. Pedro F. Nunes, Kathryn Ledbetter, Elisa Biasin, Martin Centurion, Zhijiang Chen, Amy A. Cordones, Christopher Crissman, Daniel P. Deponte, Siegfried H. Glenzer, Ming Fu Lin, Mianzhen Mo, Conor D. Rankine, Xiaozhe Shen, Thomas J.A. Wolf, Xijie Wang
Martin Centurion Publications
Electron scattering on liquid samples has been enabled recently by the development of ultrathin liquid sheet technologies. The data treatment of liquid-phase electron scattering has been mostly reliant on methodologies developed for gas electron diffraction, in which theoretical inputs and empirical fittings are often needed to account for the atomic form factor and remove the inelastic scattering background. In this work, we present an alternative data treatment method that is able to retrieve the radial distribution of all the charged particle pairs without the need of either theoretical inputs or empirical fittings. The merits of this new method are illustrated …
Temporal Coherent Control Of Resonant Two-Photon Double Ionization Of The Hydrogen Molecule Via Doubly Excited States, Jean Marcel Ngoko Djiokap, Anthony F. Starace
Temporal Coherent Control Of Resonant Two-Photon Double Ionization Of The Hydrogen Molecule Via Doubly Excited States, Jean Marcel Ngoko Djiokap, Anthony F. Starace
Anthony F. Starace Publications
We use time-delayed, counter-rotating, circularly polarized few-cycle attosecond nonoverlapping pulses to study the temporal coherent control of the resonant process of two-photon double ionization (TPDI) of hydrogen molecule via doubly excited states for pulse propagation direction along ˆk either parallel or perpendicular to the molecular axis ˆR. For ˆk ‖ ˆR and a pulse carrier frequency of 36 eV resonantly populating the Q2 1∏ + u (1) doubly excited state as well as other 1∏ + u doubly excited states, we find that the indirect ionization pathway through these doubly excited states changes the character of the kinematical vortex-shaped …
Magnetism In Curved Geometries, Robert Streubel, Evgeny Y. Tsymbal, Peter Fischer
Magnetism In Curved Geometries, Robert Streubel, Evgeny Y. Tsymbal, Peter Fischer
Robert Streubel Papers
Curvature impacts physical properties across multiple length scales, ranging from the macroscopic scale, where the shape and size vary drastically with the curvature, to the nanoscale at interfaces and inhomogeneities in materials with structural, chemical, electronic, and magnetic short-range order. In quantum materials, where correlations, entanglement, and topology dominate, the curvature opens the path to novel characteristics and phenomena that have recently emerged and could have a dramatic impact on future fundamental and applied studies of materials. Particularly, magnetic systems hosting non-collinear and topological states and 3D magnetic nanostructures strongly benefit from treating curvature as a new design parameter to …
Ultrafast Spin-Currents And Charge Conversion At 3d-5d Interfaces Probed By Time-Domain Terahertz Spectroscopy, T. H. Dang, J. Hawecker, E. Rongione, G. Baez Flores, D. Q. To, J. C. Rojas-Sanchez, H. Nong, J. Mangeney, J. Tignon, F. Godel, S. Collin, P. Seneor, M. Bibes, A. Fert, M. Anane, J. M. George, L. Vila, M. Cosset-Cheneau, D. Dolfi, R. Lebrun, P. Bortolotti, Kirill Belashchenko, S. Dhillon, H. Jaffrès
Ultrafast Spin-Currents And Charge Conversion At 3d-5d Interfaces Probed By Time-Domain Terahertz Spectroscopy, T. H. Dang, J. Hawecker, E. Rongione, G. Baez Flores, D. Q. To, J. C. Rojas-Sanchez, H. Nong, J. Mangeney, J. Tignon, F. Godel, S. Collin, P. Seneor, M. Bibes, A. Fert, M. Anane, J. M. George, L. Vila, M. Cosset-Cheneau, D. Dolfi, R. Lebrun, P. Bortolotti, Kirill Belashchenko, S. Dhillon, H. Jaffrès
Kirill Belashchenko Publications
Spintronic structures are extensively investigated for their spin-orbit torque properties, required for magnetic commutation functionalities. Current progress in these materials is dependent on the interface engineering for the optimization of spin transmission. Here, we advance the analysis of ultrafast spin-charge conversion phenomena at ferromagnetic-Transition metal interfaces due to their inverse spin-Hall effect properties. In particular, the intrinsic inverse spin-Hall effect of Pt-based systems and extrinsic inverse spin-Hall effect of Au:W and Au:Ta in NiFe/Au:(W,Ta) bilayers are investigated. The spin-charge conversion is probed by complementary techniques-ultrafast THz time-domain spectroscopy in the dynamic regime for THz pulse emission and ferromagnetic resonance spin-pumping …
The Importance Of Frontier Orbital Symmetry In The Adsorption Of Diiodobenzene On Mos2(0001), Prescott E. Evans, Zahra Hooshmand, Talat S. Rahman, Peter Dowben
The Importance Of Frontier Orbital Symmetry In The Adsorption Of Diiodobenzene On Mos2(0001), Prescott E. Evans, Zahra Hooshmand, Talat S. Rahman, Peter Dowben
Peter Dowben Publications
Evidence of a role of frontier orbital symmetry, in the adsorption process of diiodobenzene on MoS2(0001), appears in the huge differences in the rate of adsorption between 1,3-diiodobenzene, 1,2-diiodobenzene and 1,4-diiodobenzene isomers on MoS2. Experiments indicate that the rate of adsorption of 1,3-diiodobenzene on MoS2(0001) is much greater than that of the 1,2-diodobenzene and 1,4-diiodbenzene isomers. As the differences in calculated diiodobenzene isomer-MoS2 system adsorption energies and electron affinities are negligible, frontier orbital symmetry appears to play a significant role in diiodobenzene adsorption on MoS2(0001). The experimental and theory results, in combination, suggest …
Proximity-Induced Magnetization In Graphene: Towards Efficient Spin Gating, Mihovil Bosnar, Ivor Lončarić, P. Lazić, Kirill Belashchenko, Igor Žutić
Proximity-Induced Magnetization In Graphene: Towards Efficient Spin Gating, Mihovil Bosnar, Ivor Lončarić, P. Lazić, Kirill Belashchenko, Igor Žutić
Kirill Belashchenko Publications
Gate-tunable spin-dependent properties could be induced in graphene at room temperature through the magnetic proximity effect by placing it in contact with a metallic ferromagnet. Because strong chemical bonding with the metallic substrate makes gating ineffective, an intervening passivation layer is needed. Previously considered passivation layers result in a large shift of the Dirac point away from the Fermi level, so that unrealistically large gate fields are required to tune the spin polarization in graphene (Gr). We show that a monolayer of Au or Pt used as the passivation layer between Co and graphene brings the Dirac point closer to …
Detection Of Uncompensated Magnetization At The Interface Of An Epitaxial Antiferromagnetic Insulator, Pavel N. Lapa, Min Han Lee, Igor V. Roshchin, Kirill Belashchenko, Ivan K. Schuller
Detection Of Uncompensated Magnetization At The Interface Of An Epitaxial Antiferromagnetic Insulator, Pavel N. Lapa, Min Han Lee, Igor V. Roshchin, Kirill Belashchenko, Ivan K. Schuller
Kirill Belashchenko Publications
We have probed directly the temperature and magnetic field dependence of pinned uncompensated magnetization at the interface of antiferromagnetic FeF2 with Cu, using FeF2-Cu-Co spin valves. Electrons polarized by the Co layer are scattered by the pinned uncompensated moments at the FeF2-Cu interface giving rise to giant magnetoresistance. We determined the direction and magnitude of the pinned uncompensated magnetization at different magnetic fields and temperatures using the angular dependencies of resistance. The strong FeF2 anisotropy pins the uncompensated magnetization along the easy axis independent of the cooling field orientation. Most interestingly, magnetic fields as …
Reinvestigation Of The Intrinsic Magnetic Properties Of (Fe1-Xcox)2b Alloys And Crystallization Behavior Of Ribbons, Tej Nath Lamichhane, Olena Palasyuk, Vladimir P. Antropov, Ivan A. Zhuravlev, Kirill Belashchenko, Ikenna C. Nlebedim, Kevin W. Dennis, Anton Jesche, Matthew J. Kramer, Sergey L. Bud'ko, R. William Mccallum, Paul C. Canfield, Valentin Taufour
Reinvestigation Of The Intrinsic Magnetic Properties Of (Fe1-Xcox)2b Alloys And Crystallization Behavior Of Ribbons, Tej Nath Lamichhane, Olena Palasyuk, Vladimir P. Antropov, Ivan A. Zhuravlev, Kirill Belashchenko, Ikenna C. Nlebedim, Kevin W. Dennis, Anton Jesche, Matthew J. Kramer, Sergey L. Bud'ko, R. William Mccallum, Paul C. Canfield, Valentin Taufour
Kirill Belashchenko Publications
New determination of the magnetic anisotropy from single crystals of (Fe1-xCox)2B alloys are presented. The anomalous temperature dependence of the anisotropy constant is discussed using the standard Callen-Callen theory, which is shown to be insufficient to explain the experimental results. A more material specific study using first-principles calculations with disordered moments approach gives a much more consistent interpretation of the experimental data. Since the intrinsic properties of the alloys with x=0.3-0.35 are promising for permanent magnets applications, initial investigation of the extrinsic properties are described, in particular the crystallization of melt spun ribbons with Cu, Al, …
Helmholtz Spacing Of Thin Rectangular Magnetic Field Coils, Karl J. Ahrendsen, Sarah Reyes, Timothy J. Gay
Helmholtz Spacing Of Thin Rectangular Magnetic Field Coils, Karl J. Ahrendsen, Sarah Reyes, Timothy J. Gay
Timothy J. Gay Publications
In this Note, we discuss the Helmholtz spacing for a pair of thin rectangular coils of arbitrary aspect ratio and consider how best to use such coils to compensate for Earth’s magnetic field along the coils’ Cartesian symmetry axes. Such coils are frequently used in conjunction with charged-particle beam machines. The Helmholtz spacing varies non-monotonically between that for square coils and that for four optimally spaced infinite wires. We consider other coil spacings that extend the length over which the field varies by less than some tolerance along the Cartesian symmetry axes. The calculations also provide a convenient means to …
Photodissociation Of Aqueous I 3 - Observed With Liquid-Phase Ultrafast Mega-Electron-Volt Electron Diffraction, K. Ledbetter, E. Biasin, J. P.F. Nunes, Martin Centurion, K. J. Gaffney, M. Kozina, M. F. Lin, X. Shen, J. Yang, X. J. Wang, T. J. A. Wolf, A. A. Cordones
Photodissociation Of Aqueous I 3 - Observed With Liquid-Phase Ultrafast Mega-Electron-Volt Electron Diffraction, K. Ledbetter, E. Biasin, J. P.F. Nunes, Martin Centurion, K. J. Gaffney, M. Kozina, M. F. Lin, X. Shen, J. Yang, X. J. Wang, T. J. A. Wolf, A. A. Cordones
Martin Centurion Publications
Developing femtosecond resolution methods for directly observing structural dynamics is critical to understanding complex photochemical reaction mechanisms in solution. We have used two recent developments, ultrafast mega-electron-volt electron sources and vacuum compatible sub-micron thick liquid sheet jets, to enable liquid-phase ultrafast electron diffraction (LUED). We have demonstrated the viability of LUED by investigating the photodissociation of tri-iodide initiated with a 400 nm laser pulse. This has enabled the average speed of the bond expansion to be measured during the first 750 fs of dissociation and the geminate recombination to be directly captured on the picosecond time scale.
High-Resolution Movies Of Molecular Rotational Dynamics Captured With Ultrafast Electron Diffraction, Yanwei Xiong, Kyle J. Wilkin, Martin Centurion
High-Resolution Movies Of Molecular Rotational Dynamics Captured With Ultrafast Electron Diffraction, Yanwei Xiong, Kyle J. Wilkin, Martin Centurion
Martin Centurion Publications
Imaging the structure of molecules during a photoinduced reaction is essential for elucidating reaction mechanisms. This requires high spatiotemporal resolution to capture nuclear motions on the femtosecond and subangstrom scale, and a sufficiently high signal level to sample their continuous evolution with high fidelity. Here we show that, using high-repetition-rate ultrafast electron diffraction, we can accurately reconstruct a movie of the coherent rotational motion of laser-aligned nitrogen molecules. We have used a tabletop 90-keV photoelectron gun to simultaneously achieve high temporal resolution of 240 fs full width at half maximum and an electron beam current that is more than an …
Indium Segregation To The Selvedge Of In4Se3 (001), Archit Dhingra, Zoe G. Marzouk, Esha Mishra, Pavlo V. Galiy, Taras M. Nenchuk, Peter Dowben
Indium Segregation To The Selvedge Of In4Se3 (001), Archit Dhingra, Zoe G. Marzouk, Esha Mishra, Pavlo V. Galiy, Taras M. Nenchuk, Peter Dowben
Peter Dowben Publications
Thermal motion of the surface atoms will lead to a decrease in photoemission intensity, while surface segregation may result in an increase of some phostoemission intensities. For In4Se3(001), both effects are seen. The Debye–Waller factor plot, based on the temperature dependent X-ray photoemission spectroscopy (XPS) measurements on In4Se3(001), suggests an upper bound of 203 ± 6 K for the effective Debye temperature, based on the surface component of the In 3d5/2 core-level. Indium is found to segregate to selvedge (subsurface region) of the crystal.
Site Selective Adsorption Of The Spin Crossover Complex Fe(Phen)2(Ncs)2 On Au(111), Sumit Beniwal, Suchetana Sarkar, Felix Baier, Birgit Weber, Peter Dowben, Axel Enders
Site Selective Adsorption Of The Spin Crossover Complex Fe(Phen)2(Ncs)2 On Au(111), Sumit Beniwal, Suchetana Sarkar, Felix Baier, Birgit Weber, Peter Dowben, Axel Enders
Peter Dowben Publications
The iron(II) spin crossover complex Fe(1,10-phenanthroline)2(NCS)2, dubbed Fe-phen, has been studied with scanning tunneling microscopy, after adsorption on the 'herringbone' reconstructed surface of Au(111) for sub-monolayer coverages. The Fe-phen molecules attach, through their NCS-groups, to the Au atoms of the fcc domains of the reconstructed surface only, thereby lifting the herringbone reconstruction. The molecules stack to form 1D chains, which run along the Au[110] directions. Neighboring Fe-phen molecules are separated by approximately 2.65 nm, corresponding to 9 atomic spacings in this direction. The molecular axis, defined by the two phenanthroline groups, is aligned perpendicular to the …
Surface Termination And Schottky-Barrier Formation Of In4Se3(001), Archit Dhingra, Pavlo V. Galiy, Lu Wang, Nataliia S. Vorobeva, Alexey Lipatov, Angel Torres, Taras M. Nenchuk, Simeon J. Gilbert, Alexander Sinitskii, Andrew J. Yost, Wai-Ning Mei, Keisuke Fukutani, Jia Shiang Chen, Peter Dowben
Surface Termination And Schottky-Barrier Formation Of In4Se3(001), Archit Dhingra, Pavlo V. Galiy, Lu Wang, Nataliia S. Vorobeva, Alexey Lipatov, Angel Torres, Taras M. Nenchuk, Simeon J. Gilbert, Alexander Sinitskii, Andrew J. Yost, Wai-Ning Mei, Keisuke Fukutani, Jia Shiang Chen, Peter Dowben
Peter Dowben Publications
The surface termination of In4Se3(001) and the interface of this layered trichalcogenide, with Au, was examined using x-ray photoemission spectroscopy. Low energy electron diffraction indicates that the surface is highly crystalline, but suggests an absence of C2v mirror plane symmetry. The surface termination of the In4Se3(001 is found, by angle-resolved x-ray photoemission spectroscopy, to be In, which is consistent with the observed Schottky barrier formation found with this n-type semiconductor. Transistor measurements confirm earlier results from photoemission, suggesting that In4Se3(001 is an n-type semiconductor, so that Schottky barrier …
Spectroscopic And Structural Probing Of Excited-State Molecular Dynamics With Time-Resolved Photoelectron Spectroscopy And Ultrafast Electron Diffraction, Yusong Liu, Spencer L. Horton, Jie Yang, J. Pedro F. Nunes, Xiaozhe Shen, Thomas J.A. Wolf, Ruaridh Forbes, Chuan Cheng, Bryan Moore, Martin Centurion, Kareem Hegazy, Renkai Li, Ming Fu Lin, Albert Stolow, Paul Hockett, Tamás Rozgonyi, Philipp Marquetand, Xijie Wang, Thomas Weinacht
Spectroscopic And Structural Probing Of Excited-State Molecular Dynamics With Time-Resolved Photoelectron Spectroscopy And Ultrafast Electron Diffraction, Yusong Liu, Spencer L. Horton, Jie Yang, J. Pedro F. Nunes, Xiaozhe Shen, Thomas J.A. Wolf, Ruaridh Forbes, Chuan Cheng, Bryan Moore, Martin Centurion, Kareem Hegazy, Renkai Li, Ming Fu Lin, Albert Stolow, Paul Hockett, Tamás Rozgonyi, Philipp Marquetand, Xijie Wang, Thomas Weinacht
Martin Centurion Publications
Pump-probe measurements aim to capture the motion of electrons and nuclei on their natural timescales (femtoseconds to attoseconds) as chemical and physical transformations take place, effectively making "molecular movies"with short light pulses. However, the quantum dynamics of interest are filtered by the coordinate-dependent matrix elements of the chosen experimental observable. Thus, it is only through a combination of experimental measurements and theoretical calculations that one can gain insight into the internal dynamics. Here, we report on a combination of structural (relativistic ultrafast electron diffraction, or UED) and spectroscopic (time-resolved photoelectron spectroscopy, or TRPES) measurements to follow the coupled electronic and …
Perspective: Ferromagnetic Liquids, Robert Streubel, Xubo Liu, Xuefei Wu, Thomas P. Russell
Perspective: Ferromagnetic Liquids, Robert Streubel, Xubo Liu, Xuefei Wu, Thomas P. Russell
Robert Streubel Papers
Mechanical jamming of nanoparticles at liquid-liquid interfaces has evolved into a versatile approach to structure liquids with solid-state properties. Ferromagnetic liquids obtain their physical and magnetic properties, including a remanent magnetization that distinguishes them from ferrofluids, from the jamming of magnetic nanoparticles assembled at the interface between two distinct liquids to minimize surface tension. This perspective provides an overview of recent progress and discusses future directions, challenges and potential applications of jamming magnetic nanoparticles with regard to 3D nano-magnetism. We address the formation and characterization of curved magnetic geometries, and spin frustration between dipole-coupled nanostructures, and advance our understanding of …
Skyrmion Fluctuations At A First-Order Phase Transition Boundary, V. Esposito, X. Y. Zheng, M. H. Seaberg, S. A. Montoya, B. Holladay, A. H. Reid, R. Streubel, J. C.T. Lee, L. Shen, J. D. Koralek, G. Coslovich, P. Walter, S. Zohar, V. Thampy, M. F. Lin, P. Hart, K. Nakahara, P. Fischer, W. Colocho, A. Lutman, F. J. Decker, S. K. Sinha, E. E. Fullerton, S. D. Kevan, S. Roy, M. Dunne, J. J. Turner
Skyrmion Fluctuations At A First-Order Phase Transition Boundary, V. Esposito, X. Y. Zheng, M. H. Seaberg, S. A. Montoya, B. Holladay, A. H. Reid, R. Streubel, J. C.T. Lee, L. Shen, J. D. Koralek, G. Coslovich, P. Walter, S. Zohar, V. Thampy, M. F. Lin, P. Hart, K. Nakahara, P. Fischer, W. Colocho, A. Lutman, F. J. Decker, S. K. Sinha, E. E. Fullerton, S. D. Kevan, S. Roy, M. Dunne, J. J. Turner
Robert Streubel Papers
Magnetic skyrmions are topologically protected spin textures with promising prospects for applications in data storage. They can form a lattice state due to competing magnetic interactions and are commonly found in a small region of the temperature - magnetic field phase diagram. Recent work has demonstrated that these magnetic quasi-particles fluctuate at the μeV energy scale. Here, we use a coherent x-ray correlation method at an x-ray free-electron laser to investigate these fluctuations in a magnetic phase coexistence region near a first-order transition boundary where fluctuations are not expected to play a major role. Surprisingly, we find that the relaxation …
Questaal: A Package Of Electronic Structure Methods Based On The Linear Muffin-Tin Orbital Technique, Dimitar Pashov, Swagata Acharya, Walter R.L. Lambrecht, Jerome Jackson, Kirill Belashchenko, Athanasios Chantis, Francois Jamet, Mark Van Schilfgaarde
Questaal: A Package Of Electronic Structure Methods Based On The Linear Muffin-Tin Orbital Technique, Dimitar Pashov, Swagata Acharya, Walter R.L. Lambrecht, Jerome Jackson, Kirill Belashchenko, Athanasios Chantis, Francois Jamet, Mark Van Schilfgaarde
Kirill Belashchenko Publications
This paper summarises the theory and functionality behind Questaal, an open-source suite of codes for calculating the electronic structure and related properties of materials from first principles. The formalism of the linearised muffin-tin orbital (LMTO) method is revisited in detail and developed further by the introduction of short-ranged tight-binding basis functions for full-potential calculations. The LMTO method is presented in both Green's function and wave function formulations for bulk and layered systems. The suite's full-potential LMTO code uses a sophisticated basis and augmentation method that allows an efficient and precise solution to the band problem at different levels of theory, …
The Emergence Of The Local Moment Molecular Spin Transistor, Guanhua Hao, Ruihua Cheng, Peter Dowben
The Emergence Of The Local Moment Molecular Spin Transistor, Guanhua Hao, Ruihua Cheng, Peter Dowben
Peter Dowben Publications
Local moment molecular systems have now been used as the conduction channel in gated spintronics devices, and some of these three terminal devices might even be considered molecular spin transistors. In these systems, the gate voltage can be used to tune the molecular level alignment, while applied magnetic fields have an influence on the spin state, altering the magnetic properties, and providing insights to the magnetic anisotropy. More recently, the use of molecular spin crossover complexes, as the conduction channel, has led to devices that are both nonvolatile and have functionality at higher temperatures. Indeed, some devices have now been …
Characterization Of A Trochoidal Electron Monochromator, Jesse Kruse
Characterization Of A Trochoidal Electron Monochromator, Jesse Kruse
Honors Theses
This thesis presents a quantitative study of a trochoidal electron monochromator and attempts to observe the 2p^53p^2 resonance in neon. A detailed description of the experimental apparatus, including the electron beam system, the vacuum system, and the light analysis system, is presented first. Then, we discuss the theory of how the electron beam is monochromatized, how we measured monochomatization, and how we analyze the light being emitted from the collision cell. The light analysis system is capable of accurately measuring the relative Stokes parameters for any polarization of light, and the electron beam system is capable of producing electron beams …
Liquid-Phase Mega-Electron-Volt Ultrafast Electron Diffraction, J. P.F. Nunes, K. Ledbetter, M. Lin, M. Kozina, D. P. Deponte, E. Biasin, Martin Centurion, C. J. Crissman, M. Dunning, S. Guillet, K. Jobe, Y. Liu, M. Mo, X. Shen, R. Sublett, S. Weathersby, C. Yoneda, T. J. A. Wolf, Jie Yang, A. A. Cordones, Xijie Wang
Liquid-Phase Mega-Electron-Volt Ultrafast Electron Diffraction, J. P.F. Nunes, K. Ledbetter, M. Lin, M. Kozina, D. P. Deponte, E. Biasin, Martin Centurion, C. J. Crissman, M. Dunning, S. Guillet, K. Jobe, Y. Liu, M. Mo, X. Shen, R. Sublett, S. Weathersby, C. Yoneda, T. J. A. Wolf, Jie Yang, A. A. Cordones, Xijie Wang
Martin Centurion Publications
The conversion of light into usable chemical and mechanical energy is pivotal to several biological and chemical processes, many of which occur in solution. To understand the structure-function relationships mediating these processes, a technique with high spatial and temporal resolutions is required. Here, we report on the design and commissioning of a liquid-phase mega-electron-volt (MeV) ultrafast electron diffraction instrument for the study of structural dynamics in solution. Limitations posed by the shallow penetration depth of electrons and the resulting information loss due to multiple scattering and the technical challenge of delivering liquids to vacuum were overcome through the use of …
Probing Ferroelectricity By X-Ray Absorption Spectroscopy In Molecular Crystals, Fujie Tang, Xuanyuan Jiang, Hsin Yu Ko, Jianhang Xu, Mehmet Topsakal, Guanhua Hao, Alpha T. N'Diaye, Peter Dowben, Deyu Lu, Xiaoshan Xu, Xifan Wu
Probing Ferroelectricity By X-Ray Absorption Spectroscopy In Molecular Crystals, Fujie Tang, Xuanyuan Jiang, Hsin Yu Ko, Jianhang Xu, Mehmet Topsakal, Guanhua Hao, Alpha T. N'Diaye, Peter Dowben, Deyu Lu, Xiaoshan Xu, Xifan Wu
Peter Dowben Publications
We carry out X-ray absorption spectroscopy experiment at the oxygen K edge in croconic acid (C5H2O5) crystal as a prototype of ferroelectric organic molecular solid, whose electric polarization is generated by proton transfer. The experimental spectrum is well reproduced by the electron-hole excitation theory simulations from configuration generated by ab initio molecular dynamics simulation. When inversion symmetry is broken in the ferroelectric state, the hydrogen bonding environment on the two bonded molecules become inequivalent. Such a difference is sensitively probed by the bound excitation in the pre-edge, which is strongly localized on the excited …
Effects Of Intrinsic Defects And Alloying With Fe On The Half-Metallicity Of Co2Mnsi, G. G. Baez Flores, Ivan A. Zhuravlev, Kirill Belashchenko
Effects Of Intrinsic Defects And Alloying With Fe On The Half-Metallicity Of Co2Mnsi, G. G. Baez Flores, Ivan A. Zhuravlev, Kirill Belashchenko
Kirill Belashchenko Publications
The electronic structure and half-metallic gap of Co2MnSi in the presence of crystallographic defects, partial Fe substitution for Mn, and thermal spin fluctuations are studied using the coherent potential approximation and the disordered local moment method. In the presence of 5% Co or Mn vacancies the Fermi level shifts down to the minority-spin valence-band maximum. In contrast to NiMnSb, both types of Mn antisite defects in Co2MnSi are strongly exchange coupled to the host magnetization, and thermal spin fluctuations do not strongly affect the half-metallic gap. Partial substitution of Mn by Fe results in considerable changes in the Bloch spectral …
Overview Of Trends In Indian Optics Research (2008 – 2018), Mallikarjun Kappi, Biradar B S
Overview Of Trends In Indian Optics Research (2008 – 2018), Mallikarjun Kappi, Biradar B S
Library Philosophy and Practice (e-journal)
The present study deals with the assessment of Indian optics research output as reflected in Web of Science (WOS) database for the period 2008 to 2018 for identifying the research output in the field of optics literature. It also provides a comparative evaluation and performance of different types of scientometric indicators, such as number of publications, number of citations and collaboration from India. The Indian optics research has increased exponentially over the last decade.