Band structure related wave function symmetry of amphoteric Si dopants in GaAs

TL;DR

This study uses high-resolution scanning tunneling spectroscopy to analyze the wave function symmetry of amphoteric silicon dopants in GaAs, revealing distinct electronic contrasts for donors and acceptors related to their wave function distributions.

Contribution

It provides detailed imaging of Si dopant states in GaAs, linking contrast features to wave function symmetry and tunneling processes at the valence band edge.

Findings

Si(Ga) donors show radially symmetric contrasts

Si(As) acceptors display anisotropic features

Contrast differences are related to wave function symmetry and tunneling

Abstract

Autocompensated Si-doped GaAs is studied with cross-sectional scanning tunneling spectroscopy (X-STS). The local electronic contrasts of substitutional Si(Ga) donors and Si(As) acceptors under the (110) cleavage plane are imaged with high resolution. Si(Ga) donor atoms exhibit radially symmetric contrasts. Si(As) acceptors have anisotropic features. The anisotropic acceptor contrasts are traced back to a tunnel process at the valence band edge. They reflect the probability density distribution of the localized acceptor hole state.