Theory of transport through noncollinear single-electron spin-valve transistors

TL;DR

This paper investigates how Coulomb interactions, spin accumulation, and exchange fields influence electronic transport in a noncollinear single-electron spin-valve transistor, revealing high gate-voltage sensitivity of the island's spin orientation.

Contribution

It introduces a detailed analysis of the exchange field effects in noncollinear spin-valve transistors, combining Coulomb interaction and tunnel coupling impacts on transport.

Findings

Exchange field causes spin precession on the island.

Gate voltage significantly affects spin orientation.

Transport behavior varies between linear and nonlinear regimes.

Abstract

We study the electronic transport through a noncollinear single-electron spin-valve transistor. It consists of a small metallic island weakly coupled to two ferromagnetic leads with noncollinear magnetization directions. The electric current is influenced by Coulomb charging and by spin accumulation. Furthermore, the interplay of Coulomb interaction and tunnel coupling to spin-polarized leads yields a many-body exchange field, in which the accumulated island spin precesses. We analyze the effects of this exchange field in both the linear and nonlinear transport regime. In particular, we find that the exchange field can give rise to a high sensitivity of the island's spin orientation on the gate voltage.