Spatial structure of an individual Mn acceptor in GaAs

TL;DR

This study visualizes the spatial structure of a hole bound to a Mn acceptor in GaAs using STM, revealing anisotropic, cross-like wave functions caused by crystal symmetry, impacting dopant interactions.

Contribution

It provides the first direct spatial mapping of Mn acceptor wave functions in GaAs and compares experimental results with theoretical models to explain anisotropy.

Findings

Observed anisotropic, cross-like wave function shape.

Confirmed anisotropy arises from cubic crystal symmetry.

Implications for anisotropic dopant coupling in GaMnAs.

Abstract

The wave function of a hole bound to an individual Mn acceptor in GaAs is spatially mapped by scanning tunneling microscopy at room temperature and an anisotropic, cross-like shape is observed. The spatial structure is compared with that from an envelope-function, effective mass model, and from a tight-binding model. This demonstrates that anisotropy arising from the cubic symmetry of the GaAs crystal produces the cross-like shape for the hole wave-function. Thus the coupling between Mn dopants in GaMnAs mediated by such holes will be highly anisotropic.