Spin blockade at semiconductor/ferromagnet junctions

TL;DR

This paper theoretically investigates spin blockade phenomena at semiconductor/ferromagnet interfaces, revealing how minority spin clouds can limit current flow and proposing methods to test these effects experimentally.

Contribution

It introduces a theoretical model of spin blockade caused by minority spin clouds at semiconductor/ferromagnet junctions, predicting critical current limits.

Findings

Identification of spin-dipole formation near the interface

Prediction of a critical current causing spin blockade

Proposal of experimental tests for the phenomena

Abstract

We study theoretically extraction of spin-polarized electrons at nonmagnetic semiconductor/ferromagnet junctions. The outflow of majority spin electrons from the semiconductor into the ferromagnet leaves a cloud of minority spin electrons in the semiconductor region near the junction, forming a local spin-dipole configuration at the semiconductor/ferromagnet interface. This minority spin cloud can limit the majority spin current through the junction creating a pronounced spin-blockade at a critical current. We calculate the critical spin-blockade current in both planar and cylindrical geometries and discuss possible experimental tests of our predictions.