Non-Zeeman splitting for a spin-resolved STM with a Kondo adatom in a spin-polarized two-dimensional electron gas

TL;DR

This paper presents a theoretical analysis of spin-resolved local density of states in a spin-polarized 2D electron gas with a Kondo adatom, revealing non-Zeeman spin-splitting effects observable without strong magnetic fields.

Contribution

It introduces an analytical expression for SR-LDOS considering phase shifts and Fano interference, demonstrating spin-splitting of the Kondo resonance without large magnetic fields.

Findings

Non-Zeeman spin-splitting observed in total LDOS.

Analytical SR-LDOS expression derived in low temperature regime.

Results align with recent experimental observations.

Abstract

We theoretically investigate the spin-resolved local density of states (SR-LDOS) of a spin-polarized two-dimensional electron gas in the presence of a Kondo adatom and a STM probe. Using Green function formalism and the atomic approach in the limit of infinite Coulomb correlation, it is found an analytical SR-LDOS expression in the low temperature regime of the system. This formal result is given in terms of phase shifts originated by the adatom scattering and Fano interference. The SR-LDOS is investigated as a function of the probe position and different Fano factors. Our findings provide an alternative way to spin-split the Kondo resonance without the use of huge magnetic fields, typically necessary in adatom systems characterized by large Kondo temperatures. We observe a non-Zeeman spin-splitting of the Kondo resonance in the total LDOS, with one spin-component pinned around the host Fermi level. Interestingly, this result is in accordance to recent experimental data reported in Phys. Rev. B 82, 020406(R) (2010).