Theory of magnetic bipolar transistors

TL;DR

This paper introduces the concept and theoretical framework of magnetic bipolar transistors, highlighting how spin properties influence their operation and potential for magnetic control of current amplification.

Contribution

It develops a theoretical model for ideal magnetic bipolar transistors, demonstrating spin injection and magnetic control of current gain in the forward active regime.

Findings

Source spin can be injected from emitter to collector.

Electrical current gain can be controlled by magnetic field and source spin.

The theory applies to transistors with magnetic regions in the emitter, base, or collector.

Abstract

The concept of a magnetic bipolar transistor (MBT) is introduced. The transistor has at least one magnetic region (emitter, base, or collector) characterized by spin-splitting of the carrier bands. In addition, nonequilibrium (source) spin in MBTs can be induced by external means (electrically or optically). The theory of ideal MBTs is developed and discussed in the forward active regime where the transistors can amplify signals. It is shown that source spin can be injected from the emitter to the collector. It is predicted that electrical current gain (amplification) can be controlled effectively by magnetic field and source spin.