Analysis of the inelastic contribution to atomic spin excitation spectroscopy

TL;DR

This paper studies how inelastic spin excitation signals in scanning tunneling spectroscopy vary with experimental conditions on Fe adsorbates, emphasizing the importance of tip-sample distance effects.

Contribution

It introduces a model that accounts for tip-sample distance dependence to explain variations in inelastic tunneling spectra for Fe adsorbates.

Findings

Inelastic contribution varies with doping and tunnel resistance.

Tip-sample distance significantly influences inelastic spectra.

Model successfully explains observed spectral variations.

Abstract

We investigate the dependence of the inelastic spin excitation contribution to scanning tunneling spectroscopy recorded above Fe adsorbates on the InSb(110) surface at subkelvin temperatures, on bulk doping and tunnel junction resistance. To explain our observations, we show how the inelastic contribution depends on the parameters describing the excitation mechanism and tunnel conditions, in the framework of a recently developed model. We conclude that in this particular system of an adsorbate which is strongly relaxed into the substrate, the tip-sample distance dependent by-tunneling has to be taken into account in order to explain the observed variations in the inelastic tunnel spectra.