Charge Transfer and Core-Hole Screening in Stoichiometric GaAs from Auger Parameter Shifts Within a Dirac–Fock Potential Model

Objectives We use Auger parameter (AP) shifts to quantify element-resolved charge transfer and core-hole screening in stoichiometric gallium arsenide (GaAs). The objective is to verify whether the Cole -Gregory -Weightman (CGW) Dirac -Fock (DF) potential model, combined with a dielectric-screened relaxation term, can provide a self-consistent III -V benchmark beyond the earlier InSb case. Material and Methods The analysis relies on critically evaluated Ga and As spectroscopic data from National Bureau of Standards (NBS)/National Institute of Standards and Technology (NIST) Technical Note 1289, together with DF-derived one-center parameters and a high-frequency dielectric constant. Charge neutrality and a common screening length for the two sublattices are imposed to solve the coupled Ga/As AP-shift equations. Results The solution yields Å and , where . The direction of transfer is consistent with electronegativity-based expectations for bond polarity. A benchmark based on the Cossu compilation provides Å and , indicating that the inferred screening length is relatively insensitive to reasonable variations in the adopted dataset, whereas the charge-transfer magnitude is more dataset dependent. Conclusion These results suggest short-range extra-atomic screening at the scale of the first coordination shell and a moderately polar, far from fully ionic, Ga -As bond. Together with the earlier InSb study, this work provides a second III -V benchmark and further supports the applicability of the CGW potential model for separating ground-state charge transfer from final-state screening in core-level photoemission.