Electron-ion coupling in semiconductors beyond Fermi's golden rule

0502425 - FZÚ 2019 RIV US eng J - Journal Article
Medvedev, Nikita - Li, Z. - Tkachenko, V. - Ziaja, B.
Electron-ion coupling in semiconductors beyond Fermi's golden rule.
Physical Review B. Roč. 95, č. 1 (2017), s. 1-10, č. článku 014309. ISSN 2469-9950. E-ISSN 2469-9969
R&D Projects: GA MŠMT LG15013
Institutional support: RVO:68378271
Keywords : warm dense matter * relaxation-time approximation * Lindhard dielectric function * femtosecond laser-pulses * fel-pulse * duration monitor
OECD category: Atomic, molecular and chemical physics (physics of atoms and molecules including collision, interaction with radiation, magnetic resonances, Mössbauer effect)
Impact factor: 3.813, year: 2017

In the present work, a theoretical study of electron-phonon (electron-ion) coupling rates in semiconductors driven out of equilibrium is performed. Transient change of optical coefficients reflects the band gap shrinkage in covalently bonded materials, and thus, the heating of atomic lattice. Utilizing this dependence, we test various models of electron-ion coupling. The simulation technique is based on tight-binding molecular dynamics. Our simulations with the dedicated hybrid approach (XTANT) indicate that the widely used Fermi’s golden rule can break down describing material excitation on femtosecond time scales. In contrast, dynamical coupling proposed in this work yields a reasonably good agreement of simulation results with available experimental data.
Permanent Link: http://hdl.handle.net/11104/0294358