Atomic scale visualization of the p-d hybridization in III-V semiconductors doped with transition metal impurities

TL;DR

This study combines advanced microscopy, spectroscopy, and theoretical calculations to visualize and understand the atomic-scale p-d hybridization of transition metal impurities, specifically Cr, in GaAs semiconductors.

Contribution

It provides the first direct atomic-scale visualization and detailed electronic characterization of p-d hybridization in III-V semiconductors doped with transition metals.

Findings

Visualization of Cr impurity wave functions showing anisotropic extension.

Identification of in-gap states associated with p-d hybridization.

Correlation of experimental data with first-principles calculations confirming hybridization.

Abstract

p-d hybridization of transition metal impurities in a semiconductor host is the mechanism that couples valence-band electrons and localized spins. We use scanning tunneling microscopy and spectroscopy combined with density functional theory to probe at the atomic scale hybridization of Cr single impurities with GaAs host. Combining spatial density of states mapping and in-gap states spectroscopy of the Cr substituted at the surface of the semiconductor, we give a detailed picture of the spatial extension and the electronic structure of the strongly anisotropic wave function of Cr on GaAs(110). First principles calculations allow to identify electronic character and origin of each states and show that the main resonance peaks and the wave function with "drop-eyes" lobes experimentally observed for 3d metal impurities in III-V semiconductor are direct local evidences of the p-d hybridization.