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

摘要

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