Spin-Polarized STM for a Kondo adatom

TL;DR

This paper explores how spin-polarized STM affects the tunneling conductance over a Kondo adatom, revealing bias-dependent splitting and asymmetry of the Kondo peak influenced by quantum interference and tip-adatom distance.

Contribution

It provides a detailed analysis of the bias dependence of conductance in spin-polarized STM over a Kondo adatom, including the effects of quantum interference and the Fano parameter.

Findings

Kondo peak splits and shows asymmetry depending on tip-adatom distance.

Increasing lateral distance suppresses the Kondo peak-splitting.

Conductance transitions to a standard Fano-Kondo profile at larger distances.

Abstract

We investigate the bias dependence of the tunneling conductance between a spin-polarized (SP) scanning tunneling microscope (STM) tip and the surface conduction states of a normal metal with a Kondo adatom. Quantum interference between tip-host metal and tip-adatom-host metal conduction paths is studied in the full range of the Fano parameter $q$. The spin-polarized STM gives rise to a splitting of the Kondo peak and asymmetry in the zero-bias anomaly depending on the lateral tip-adatom distance. For increasing lateral distances, the Kondo peak-splitting shows a strong suppression and the spin-polarized conductance exhibits the standard Fano-Kondo profile.