Magnetization-Switched Metal-Insulator Transition in a (Ga,Mn)As Tunnel Device

TL;DR

This paper demonstrates a magnetization-controlled metal-insulator transition in (Ga,Mn)As tunnel devices, where the Efros-Shklovskii gap can be reversibly tuned by changing the magnetization direction, affecting the hole wave-function distribution.

Contribution

It reveals a novel magnetization-dependent control of the metal-insulator transition via the hole wave-function in (Ga,Mn)As devices.

Findings

Efros-Shklovskii gap observed in (Ga,Mn)As tunnel junctions

Magnetization direction influences hole wave-function extent

Reversible tuning of insulating and metallic states achieved

Abstract

We observe the occurrence of an Efros-Shklovskii gap in (Ga,Mn)As based tunnel junctions. The occurrence of the gap is controlled by the extent of the hole wave-function on the Mn acceptor atoms. Using k.p-type calculations we show that this extent depends crucially on the direction of the magnetization in the (Ga,Mn)As (which has two almost equivalent easy axes). This implies one can reversibly tune the system into the insulating or metallic state by changing the magnetization.