Energy Dependent Contrast in Atomic-Scale Spin-Polarized Scanning Tunneling Microscopy ofMn3N2(010): Experiment and First-Principles Theory

TL;DR

This study combines experimental spin-polarized scanning tunneling microscopy with first-principles calculations to analyze how bias voltage influences magnetic contrast at the atomic scale on Mn3N2(010) surfaces.

Contribution

It demonstrates the voltage-dependent magnetic contrast and its inversion, validated by comparison with spin-polarized density functional theory simulations.

Findings

Magnetic contrast varies strongly with bias voltage.

Magnetic contrast inversion is observed.

Simulations successfully reproduce experimental data.

Abstract

The technique of spin-polarized scanning tunneling microscopy is investigated for its use in determining fine details of surface magnetic structure down to the atomic scale. As a model sample, the row-wise anti-ferromagnetic Mn3N2(010) surface is studied. It is shown that the magnetic contrast in atomic-scale images is a strong function of the bias voltage around the Fermi level. Inversion of the magnetic contrast is also demonstrated. The experimental SP-STM images and height profiles are compared with simulated SP-STM images and height profiles based on spin-polarized density functional theory. The success of different tip models in reproducing the non-magnetic and magnetic STM data is explored.