Electron-Hole Liquids in Polar Semiconductors

Abstract

We calculate the ground-state energy of the electron-hole liquid including the coupling to LO phonons. We find that the electron-phonon interaction increases the stability of the liquid phase relative to excitons. We apply the theory to AgBr and to the direct bandgap semiconductors CdS, CdSe, and ZnS. We find that the electron-hole liquid is strongly bound in CdS and AgBr but only weakly so in CdSe and ZnS.