Electron-hole liquid in many-band systems. II. Ge and Si

Abstract

Calculations are presented for the ground-state energy and enhancement factors for the electron-hole liquid in germanium and silicon both in the Hubbard and the self-consistent particle-hole approximations for two simplified models of the actual band structure. It is shown that the inclusion of multiple electron-hole scatterings lowers the ground-state energy by about 3 K for germanium and by about 18 K for silicon, while it raises the enhancement factors by about 20% and 50%, respectively. A detailed comparison of the experimental data with theoretical calculations is carried out and it is argued that including electron-electron and hole-hole short-range correlations would substantially improve agreement between theory and experiment.