Ab initio study of plasmons and electron-phonon coupling in bismuth: from free-carrier absorption towards a new method for electron energy-loss spectroscopy

摘要: This work has been devoted to the theoretical study of bulk semimetallic bismuth with methods based on density functional theory (DFT). Effects spin-orbit coupling and exchange-and-correlation functionals in local (LDA) generalized gradient approximation (GGA) have systematically investigated. I found that electron hole pockets at Fermi level are accurately reproduced, which enabled me successfully interpret pump-probe experiments photoexcited performed Laboratoire des Solides Irradies. The strong dependence electronic wave vector, calculated upper valence band zone-center A1g LO phonon, explains observation a strongly k-dependent oscillation amplitude time-resolved photoemission upon activation coherent phonon under photoexcitation. also shown presence extrema conduction bands structure, where carrier mass can be as large 18 m0, favours an accumulation carriers these contributes augmentation plasma frequency function time after photoexcitation, effect no analogy other materials (as yet). Finally, developed new ab initio approach time-dependent perturbation (TDDFPT), allows us calculate response for any momentum transfer. Lanczos recursion method first energy-loss spectrum Bi 0-100 eV energy range, bridging gap between core losses. opens way routine calculation surface plasmons.