Simulation of spin-polarized scanning tunneling spectroscopy on complex magnetic surfaces: Case of a Cr monolayer on Ag(111)

TL;DR

This paper introduces an efficient computational method for simulating spin-polarized scanning tunneling spectroscopy on complex magnetic surfaces, accounting for electronic structures from first principles and surpassing the LDOS approximation.

Contribution

The authors develop a novel atom-superposition-based approach for SP-STS simulation that incorporates detailed electronic structures and analyzes tip effects on spectra.

Findings

Spectra and magnetic asymmetries depend on tip electronic structure.

The method can generate 2D differential conductance maps.

Effective spin polarization maps can be qualitatively simulated.

Abstract

We propose a computationally efficient atom-superposition-based method for simulating spin-polarized scanning tunneling spectroscopy (SP-STS) on complex magnetic surfaces based on the sample and tip electronic structures obtained from first principles. We go beyond the commonly used local density of states (LDOS) approximation for the differential conductance, dI/dV. The capabilities of our approach are illustrated for a Cr monolayer on a Ag(111) surface in a noncollinear magnetic state. We find evidence that the simulated tunneling spectra and magnetic asymmetries are sensitive to the tip electronic structure, and we analyze the contributing terms. Related to SP-STS experiments, we show a way to simulate two-dimensional differential conductance maps and qualitatively correct effective spin polarization maps on a constant current contour above a magnetic surface.