Frequency-Dependent Current Noise through Quantum-Dot Spin Valves

TL;DR

This paper investigates how frequency-dependent current noise in quantum-dot spin valves reveals single-spin dynamics, showing that spin precession influences noise characteristics and can be detected via the Fano factor.

Contribution

It introduces the use of frequency-dependent Fano factor to detect single-spin precession effects in quantum-dot spin valves with non-collinear ferromagnetic leads.

Findings

Spin precession suppresses low-frequency noise due to reduced spin-selective bunching.

The noise spectrum exhibits a resonance at the Larmor frequency.

The resonance lineshape depends on the relative angle of lead magnetizations.

Abstract

We study frequency-dependent current noise through a single-level quantum dot connected to ferromagnetic leads with non-collinear magnetization. We propose to use the frequency-dependent Fano factor as a tool to detect single-spin dynamics in the quantum dot. Spin precession due to an external magnetic and/or a many-body exchange field affects the Fano factor of the system in two ways. First, the tendency towards spin-selective bunching of the transmitted electrons is suppressed, which gives rise to a reduction of the low-frequency noise. Second, the noise spectrum displays a resonance at the Larmor frequency, whose lineshape depends on the relative angle of the leads' magnetizations.