STM images of sub-surface Mn atoms in GaAs: evidence of hybridization of surface and impurity states

TL;DR

This paper demonstrates that STM images of sub-surface Mn atoms in GaAs are due to hybridization with surface states, not bulk impurity wavefunctions, supported by high-resolution imaging and tight-binding simulations.

Contribution

It provides evidence that surface and impurity states hybridize in STM images, challenging previous interpretations based solely on bulk wavefunctions.

Findings

STM images result from hybridization of impurity and surface states

High-resolution images match tight-binding simulations

Surface states significantly influence STM imaging of sub-surface impurities

Abstract

We prove that scanning tunneling microscopy (STM) images of sub-surface Mn atoms in GaAs are formed by hybridization of the impurity state with intrinsic surface states. They cannot be interpreted in terms of bulk-impurity wavefunction imaging. High atomic resolution images obtained using a low-temperature apparatus are compared with advanced, parameter-free tight-binding simulations accounting for both the buckled (110) surface and vacuum electronic properties.