External Control of a Metal-Insulator Transition in GaMnAs Wires

TL;DR

This paper theoretically investigates how a weak external magnetic field can control a metal-insulator transition in disordered ferromagnetic GaMnAs wires, revealing potential for studying quantum criticality and material properties.

Contribution

It introduces a theoretical framework showing external magnetic fields can induce a controllable metal-insulator transition in ferromagnetic semiconductors.

Findings

Disorder causes a metal-insulator transition in GaMnAs wires.

Weak magnetic fields can switch the transition on and off.

The phenomenon may extend to other materials with large anisotropic magnetoresistance.

Abstract

Quantum transport in disordered ferromagnetic (III,Mn)V semiconductors is studied theoretically. Mesoscopic wires exhibit an Anderson disorder-induced metal-insulator transition that can be controlled by a weak external magnetic field. This metal-insulator transition should also occur in other materials with large anisotropic magneto resistance effects. The transition can be useful for studies of zero-temperature quantum critical phase transitions and fundamental material properties.