Dresden 2006 – wissenschaftliches Programm
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TT: Tiefe Temperaturen
TT 18: Superconductivity: Borides, Borocarbides, Carbides, ...
TT 18.11: Vortrag
Dienstag, 28. März 2006, 17:45–18:00, HSZ 02
Superconductivity and Lattice Instability in Compressed Lithium from Fermi Surface Hot Spots — •Deepa Kasinathan1, Jan Kunes1, Amy Lazicki1,2, Helge Rosner3, Choong-shik Yoo2, Richard Scalettar1, and Warren Pickett1 — 1Dept. of Physics, University of California - Davis, CA 95616, U.S.A — 2Lawrence Livermore National Labratory, Livermore, CA — 3Max-Planck-Institute for Chemical Physics of Solids, Dresden, Germany
Lithium, a simple metal not su perconducting above 5mK at ambient pressure, becomes a 20 K superconductor at 50 GPa. This high Tc is shown to arise from critical (formally divergent) electron-phonon coupling to the transverse phonon branch along intersections of Kohn anomaly surfaces with the Fermi surface. First principles linear response calculations of the phonon spectrum and spectral function α2 F(ω) reveal (harmonic) instability already at 25 GPa. Our results imply that the fcc phase is anharmonically stabilized in the 25-38 GPa range.