Nanoscopic interferometer model for spin resonance in current noise

TL;DR

This paper presents a nanoscopic interferometer model explaining electron spin resonance observed in STM current noise, highlighting the role of spin-orbit interactions and tunneling path interference in producing resonance effects.

Contribution

It introduces a theoretical model for ESR in STM current noise that incorporates interference of tunneling paths and spin-orbit interactions, providing analytical noise spectrum predictions.

Findings

Interference of tunneling paths causes resonance in noise spectrum.

Spin-orbit interactions enable the observed ESR effect.

Analytical noise spectrum derived for non-polarized leads.

Abstract

We study a model for the observed phenomenon of electron spin resonance (ESR) at the Zeeman frequency as seen by a scanning tunneling microscope (STM) via its current noise. The model for this ESR-STM phenomenon allows the STM current to flow in two arms of a nanoscopic interferometer, one arm has direct tunneling from the tip to the substrate while the second arm has tunneling through two spin states. We evaluate analytically the noise spectrum for non-polarized leads, as relevant to the experimental setup. We show that spin-orbit interactions allow for an interference of two tunneling paths resulting in a resonance effect.