Spin accumulation in ferromagnetic single-electron transistors in the cotunneling regime

TL;DR

This paper introduces a novel method for directly detecting spin accumulation in ferromagnetic single-electron transistors, utilizing the spin-dependent current and electrochemical potential splitting to improve measurement accuracy.

Contribution

It presents a new detection technique that overcomes previous limitations by analyzing resonance spacing caused by spin-splitting in the electrochemical potentials.

Findings

Spin accumulation causes measurable resonance shifts.

The method effectively detects spin-dependent electrochemical potential splitting.

Higher order cotunneling processes are analyzed in the strong nonequilibrium regime.

Abstract

We propose a new method of direct detection of spin accumulation, which overcomes problems of previous measurement schemes. A spin dependent current in a single-electron transistor with ferromagnetic electrodes leads to spin accumulation on the metallic island. The resulting spin-splitting of the electrochemical potentials of the island, because of an additional shift by the charging energy, can be detected from the spacing between two resonances in the current-voltage characteristics. The results were obtained in the framework of a real-time diagrammatic approach which allows to study higher order (co-)tunneling processes in the strong nonequlibrium situation.