Current fluctuations of noncollinear single-electron spin-valve transistors

TL;DR

This paper analyzes how exchange interactions in a noncollinear single-electron spin-valve transistor influence charge-current fluctuations, revealing a reduction in the Fano factor due to many-particle effects.

Contribution

It provides a theoretical study of finite-frequency and zero-frequency charge-current fluctuations considering exchange fields in noncollinear spin-valve transistors.

Findings

Exchange field reduces the sub-Poissonian Fano factor.

Spin-dependent tunneling affects current noise characteristics.

Many-particle interactions significantly influence charge fluctuations.

Abstract

We theoretically investigate the finite-frequency as well as the zero-frequency charge-current fluctuations through a noncollinear single-electron spin-valve transistor in the limit of sequential tunneling. The system under consideration consists of two tunnel junctions that connect a small central metallic island to two ferromagnetic leads with noncollinear magnetization. Due to the spin-dependent tunnel coupling and the electron-electron interaction on the central electrode an exchange field that acts on the accumulated island spin is present. We analyze how this many-particle interaction effect influences the current noise. In detail, we present that the field leads to a reduction of the sub-Poissonian Fano factor.