Determining the spin-orbit coupling via spin-polarized spectroscopy of magnetic impurities

TL;DR

This paper demonstrates that spin-polarized spectroscopy of magnetic impurities can accurately determine the strength of spin-orbit coupling in low-dimensional systems, a task not possible with non-spin-polarized methods.

Contribution

It introduces a method combining numerical and analytical approaches to extract spin-orbit coupling strength from spin-polarized LDOS measurements.

Findings

Fourier transform of spin-polarized LDOS reveals spin-orbit coupling strength

Magnetic impurities are essential for measuring spin-orbit coupling

Non-spin-polarized experiments cannot access spin-orbit coupling value

Abstract

We study the spin-resolved spectral properties of the impurity states associated to the presence of magnetic impurities in two-dimensional, as well as one-dimensional systems with Rashba spin-orbit coupling. We focus on Shiba bound states in superconducting materials, as well as on impurity states in metallic systems. Using a combination of a numerical T-matrix approximation and a direct analytical calculation of the bound state wave function, we compute the local density of states (LDOS) together with its Fourier transform (FT). We find that the FT of the spin-polarized LDOS, a quantity accessible via spin-polarized STM, allows to accurately extract the strength of the spin-orbit coupling. Also we confirm that the presence of magnetic impurities is strictly necessary for such measurement, and that non-spin-polarized experiments cannot have access to the value of the spin-orbit coupling.