One-Electron Broken-Symmetry Approach to the Core-Hole Spectra of Semiconductors

It is shown that in contrast to band theory, a self-consistent one-electron model with broken symmetries (crystal orbitals are not constrained to be Bloch periodic) provides a physical description of core-ionization, core-exciton, and core-to-conduction-band transition energies in semiconductors. Application to GaP shows that a hitherto unrecognized factor---the screening of the core-hole self-energy by the electron orbit---can explain many of the outstanding puzzles in core-hole spectra.