Quasiparticle Calculations for Point Defects on Semiconductor Surfaces

TL;DR

This paper presents a method combining plane-wave pseudopotential calculations and GW quasiparticle corrections to accurately determine the electronic structure of point defects on semiconductor surfaces, exemplified by the As vacancy on GaAs(110).

Contribution

It introduces an ab initio approach for quasiparticle calculations of surface point defects, improving the accuracy of defect state energy predictions.

Findings

The vacancy state shifts from 0.06 to 0.65 eV above the valence band maximum after GW correction.

The GW results closely match experimental surface photovoltage measurements.

The method effectively captures defect electronic structures on semiconductor surfaces.

Abstract

We discuss the implementation of quasiparticle calculations for point defects on semiconductor surfaces and, as a specific example, present an ab initio study of the electronic structure of the As vacancy in the +1 charge state on the GaAs(110) surface. The structural properties are calculated with the plane-wave pseudopotential method, and the quasiparticle energies are obtained from Hedin's GW approximation. Our calculations show that the 1a" vacancy state in the band gap is shifted from 0.06 to 0.65 eV above the valence-band maximum after the self-energy correction to the Kohn-Sham eigenvalues. The GW result is in close agreement with a recent surface photovoltage imaging measurement.