The Structure of GaSb Digitally Doped with Mn

TL;DR

This study combines experimental XSTM imaging and theoretical DFT calculations to analyze the structural configurations of Mn dopants in GaSb, revealing distinct appearances of isolated Mn and MnSb clusters.

Contribution

It provides a detailed characterization of Mn dopant configurations in GaSb using combined microscopy and computational methods, highlighting their different structural signatures.

Findings

Isolated Mn appears higher in filled-state XSTM images.

MnSb clusters cause surface relaxation and appear as depressions.

Different Mn forms have distinct XSTM signatures.

Abstract

Cross sectional scanning tunneling microscopy (XSTM) and density functional theory have been used to characterize the structure of GaSb digitally doped with Mn. The Mn dopants are found in both isolated substitutional form as well as in large clusters of zinc-blende MnSb commensurate with the surrounding GaSb matrix. Theoretical calculations predict that these two forms of Mn in the digitally doped layers will have a very different appearance in XSTM images. Substitutional Mn enhances the local density of states near the surface, thus appearing higher in a filled-state image. In contrast, MnSb clusters induce substantial structural relaxation at the {110} surface, and therefore appear as localized depressed regions with negligible perturbation of the surrounding GaSb.