Electron short-wave phonon scattering in crystals with chalcopyrite lattice

Abstract

Electron short-wavelength phonon scattering is an effective channel for energy relaxation in crystals with a pseudo-direct optical gap. The equilibrium parameters of crystal structures and spectra of electrons and phonons in the ternary chalcopyrite compounds ZnSiP2 and ZnGeP2 are calculated self-consistently in good agreement with available experimental and theoretical calculations. The ab initio probabilities of phonon-assisted intervalley scattering of electrons in the conduction bands of the pseudo-direct-gap compounds ZnSiP2 and ZnGeP2 between the central Γ minima and the lowest lateral minima (valleys) at the T and N points have been calculated using the density functional perturbation theory. Electron–phonon scattering rates associated with intervalley phonons are calculated. Coupling constants for intervalley phonons in the chalcopyrite phosphides are close to their values in Si, Ge, and in the binary analog GaP.