Spin Excitations and Correlations in Scanning Tunneling Spectroscopy

TL;DR

This paper demonstrates that perturbation theory can accurately model spin excitations observed in scanning tunneling spectroscopy, including complex correlated systems, providing a practical tool for experimental analysis.

Contribution

It introduces an expanded scattering model that efficiently describes complex spin systems and their correlations, enhancing understanding of tunneling transport in these quantum systems.

Findings

Perturbation theory accurately reproduces differential conductance in spin systems.

Expanded models include Kondo-like interactions for complex spin arrangements.

Correlations between spins and bath electrons are elucidated and linked to tunable parameters.

Abstract

In recent years inelastic spin-flip spectroscopy using a lowtemperature scanning tunneling microscope has been a very successful tool for studying not only individual spins but also complex coupled systems. When these systems interact with the electrons of the supporting substrate correlated manyparticle states can emerge, making them ideal prototypical quantum systems. The spin systems, which can be constructed by arranging individual atoms on appropriate surfaces or embedded in synthesized molecular structures, can reveal very rich spectral features. Up to now the spectral complexity has only been partly described. This manuscript shows that perturbation theory enables one to describe the tunneling transport, reproducing the differential conductance with surprisingly high accuracy. Well established scattering models, which include Kondo-like spin-spin and potential interactions, are expanded to enable calculation of arbitrary complex spin systems in reasonable time scale and the extraction of important physical properties. The emergence of correlations between spins and, in particular, between the localized spins and the supporting bath electrons are discussed and related to experimentally tunable parameters. These results might stimulate new experiments by providing experimentalists with an easily applicable modeling tool.