Electrically controlled quantum dot based spin current injector

TL;DR

This paper proposes a fully electrically controllable quantum dot device that acts as a fast, switchable spin current injector with high polarization, tunable by gate and bias voltages, suitable for advanced nanostructures.

Contribution

It introduces a novel quantum dot based spin injector that is electrically controlled and capable of rapid switching, enhancing spintronic device functionality.

Findings

Achieves near full spin polarization of current.

Demonstrates sign reversal of polarization via voltage control.

Operates with nanosecond switching times.

Abstract

We present a proposal for a fully electrically controllable quantum dot based spin current injector. The device consists of a quantum dot that is strongly coupled to a ferromagnetic electrode on one side and weakly coupled to a nonmagnetic electrode on the other side. The presence of ferromagnetic electrode results in an exchange field that splits the dot level. We show that this exchange-induced splitting can lead to almost full spin polarization of the current flowing through the device. Moreover, we also demonstrate that the sign of the polarization can be changed by the gate or the bias voltage within a switching time in the nanosecond range. Thus the proposed device can operate as an electrically controlled, fast switchable spin current source, which can be realized in various state-of-the-art nanostructures.