Electron-hole interaction in the d-electron excitations of GeS and SnS

Abstract

The excitation energy of the Ge 3d and Sn 4d electrons in GeS and SnS is consistently 0.7 to 1.7 eV lower than one would expect from a combination of photoemission binding energies and optical interband transitions connecting valence and conduction bands. This, as well as the reversal of the intensity ratio of d52 and d32 excitations, is an indication for non-negligible d-hole conduction-electron interactions. © 1977 The American Physical Society.