Electron Paramagnetic Resonance of Single Magnetic Moment on a Surface

TL;DR

This paper investigates electron spin resonance of single magnetic moments on surfaces, demonstrating how electric fields and spin-polarized currents influence tunneling current and explaining differences in resonance signals for integer versus half-integer spins.

Contribution

It introduces a model linking electric field frequency, spin-polarized current, and local spin dynamics, explaining ESR signals based on spin quantization.

Findings

Tunneling current depends on local magnetic moments.

Electric field frequency mixes with Larmor frequency.

Resonance signals differ for integer and half-integer spins.

Abstract

We address electron spin resonance of single magnetic moments in a tunnel junction using time-dependent electric fields and spin-polarized current. We show that the tunneling current directly depends on the local magnetic moment and that the frequency of the external electric field mixes with the characteristic Larmor frequency of the local spin. The importance of the spin-polarized current induced anisotropy fields acting on the local spin moment is, moreover, demonstrated. Our proposed model thus explains the absence of an electron spin resonance for a half integer spin, in contrast with the strong signal observed for an integer spin.