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Full-Text Articles in Physics
Plasma Oscillations And Expansion Of An Ultracold Neutral Plasma, Scott D. Bergeson, S. Kulin, T. C. Killian, S. L. Rolston
Plasma Oscillations And Expansion Of An Ultracold Neutral Plasma, Scott D. Bergeson, S. Kulin, T. C. Killian, S. L. Rolston
Faculty Publications
We report the observation of plasma oscillations in an ultracold neutral plasma. With this collective mode we probe the electron density distribution and study the expansion of the plasma as a function of time. For classical plasma conditions, i.e., weak Coulomb coupling, the expansion is dominated by the pressure of the electron gas and is described by a hydrodynamic model. Discrepancies between the model and observations at low temperature and high density may be due to strong coupling of the electrons.
Electronic Structure Of Bas And Boride Iii-V Alloys, Gus L. W. Hart, Alex Zunger
Electronic Structure Of Bas And Boride Iii-V Alloys, Gus L. W. Hart, Alex Zunger
Faculty Publications
Boron arsenide, the typically ignored member of the Group-III–V arsenide series BAs-AlAs-GaAs-InAs is found to resemble silicon electronically: its Γ conduction-band minimum is p-like (Γ15), not s-like (Γ1c), it has an X1c-like indirect band gap, and its bond charge is distributed almost equally on the two atoms in the unit cell, exhibiting nearly perfect covalency. The reasons for these are tracked down to the anomalously low atomic p orbital energy in the boron and to the unusually strong s–s repulsion in BAs relative to most other Group-III–V compounds. We find unexpected valence-band offsets of BAs with respect to GaAs and …
Average Energy Flow Of Optical Pulses In Dispersive Media, Scott Glasgow, Michael Ware, Justin Peatross
Average Energy Flow Of Optical Pulses In Dispersive Media, Scott Glasgow, Michael Ware, Justin Peatross
Faculty Publications
The arrival time of a light pulse at a point in space is defined using a time expectation integral over the Poynting vector. The delay between pulse arrival times at two distinct points is shown to consist of two parts: a spectral superposition of group delays (inverse of group velocity) and a delay due to spectral reshaping via absorption or amplification. The result provides a context wherein group velocity is always meaningful even for broad band pulses and when the group velocity is superluminal or negative. The result imposes luminality on sharply defined pulses.
Electronic Structure Of Cu1-Xnixrh2s4 And Curh2se4: Band-Structure Calculations, X-Ray Photoemission, And Fluorescence Measurements, Gus L. W. Hart, W. E. Pickett, E. Z. Kurmaev, M. Neumann, D. Hartmann, A. Moewes, D. L. Ederer, R. Endoh, K. Taniguchi, S. Nagata
Electronic Structure Of Cu1-Xnixrh2s4 And Curh2se4: Band-Structure Calculations, X-Ray Photoemission, And Fluorescence Measurements, Gus L. W. Hart, W. E. Pickett, E. Z. Kurmaev, M. Neumann, D. Hartmann, A. Moewes, D. L. Ederer, R. Endoh, K. Taniguchi, S. Nagata
Faculty Publications
The electronic structure of spinel-type Cu1-xNixRh2S4 (x=0.0, 0.1, 0.3, 0.5, 1.0) and CuRh2Se4 compounds has been studied by means of x-ray photoelectron (SPS) and fluorescent spectroscopy. Cu L3, Ni L3, S L2,3, and Se M2,3 x-ray emission spectra (XES) were measured near thresholds at Beamline 8.0 of the Lawrence Berkeley Laboratory's Advanced Light Source. XES measurements of the constituent atoms of these compounds, reduced to the same binding energy scale, are found to be in excellent agreement with XPS valence bands. The calculated XES spectra which include dipole matrix elements show that the partial density of states reproduce experimental spectra …