Electron-phonon coupling in metals at high electronic temperatures

Even though electron-phonon coupling is one of the most important parameters governing material evolution after ultrafast energy deposition it remains the most unexplored one. In this work we apply the dynamical coupling approach to calculate the nonadiabatic electron-ion energy exchange in nonequilibrium solids with the electronic temperature high above the atomic one. It is implemented into the tight-binding molecular dynamics code and used to study electron-phonon coupling in various elemental metals. The approach developed is a universal scheme applicable to electronic temperatures up to a few electron volts and to arbitrary atomic configurations and dynamics. We demonstrate that the calculated electron-ion (electron-phonon) coupling parameter agrees well with the available experimental data in the high-electronic-temperature regime, validating the model. The following materials are studied here: fcc metals Al, Ca, Ni, Cu, Sr, Y, Zr, Rh, Pd, Ag, Ir, Pt, Au, and Pb; hcp metals Mg, Sc, Ti, Co, Zn, Tc, Ru, Cd, Hf, Re, and Os; bcc metals V, Cr, Fe, Nb, Mo, Ba, Ta, and W; a diamond cubic lattice metal Sn; specific cases of Ga, In, Mn, Te, and Se; and additionally semimetal graphite and the semiconductors Si and Ge. For these materials, we provide an estimation of the electron-phonon coupling at elevated electron temperatures, which can be used in various models simulating ultrafast energy deposition in matter. We also discuss the dependence of the coupling parameter on atomic mass, temperature, and density.