Temperature Coefficients of Energy Separations between Ga3dCore Levels andsp3Valence-Conduction Bands in GaP

The measured temperature coefficients of the energy separations between the Ga $3d$ core levels and the top (${{\Gamma }_8}^V$) and bottom (${X_6}^C$) of the $s{p}^3$ valence and conduction bands in GaP between 110 K and 295 K are (+1.0±0.5)×${10}^{-4\mathrm{}}$ eV ${\mathrm{K}}^{-1\mathrm{}}$ and (-2.4±0.5)×${10}^{-4\mathrm{}}$ eV ${\mathrm{K}}^{-1\mathrm{}}$, respectively. They are described within experimental accuracy by the Debye-Waller, hydrostatic, self-energy, and spatially averaged screened-ion core potential interactions of the $s{p}^3$ bands alone. No significant core-level contribution is observed.