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Full-Text Articles in Condensed Matter Physics
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 …