The Effect of Many‐Electron Correlation on Photothresholds of Semiconductors and Valence Band Discontinuities at Heterojunctions

Abstract Photothresholds of semiconductors are known to deviate by 3 to 4 eV from the predictions of one‐electron band theory. It is shown that these discrepancies are due to many‐electron correlation effects, in particular, to electronic relaxation. The corrections to photothresholds due to electronic relaxation are calculated by means of Green's function technique applying the linear shielded potential approximation to the exchange‐correlation self‐energy. Within the uncertainties of LCAO theories the calculated photothresholds of group IV, III‐V, and II‐VI semiconductors agree with experimental data. A simple physical picture of the correlation effect is provided. Relaxation corrections to valence band discontinuities from one‐electron band theories are also calculated.