Controllable spin-filtering and magnetoconductance in a novel hybrid FM/2DEG/FM structure

Abstract

Spin-dependent ballistic transport is studied for a two-dimensional electron gas (2DEG) heterostructure, sandwiched between two ferromagnetic metal (FM) layers. The device exhibits a strong spin-filtering behavior when the magnetization directions of the FM layers are anti-parallel to one another. Additionally, a pronounced magnetoconductance (MC) effect is predicted when the relative magnetization direction of the FM layers is changed, e.g. by applying an external magnetic field sweep. Both the spin-filter and spin-valve (SV) functions can be tuned externally by adjusting the applied voltage and the fringe field strength from the FM layers. Compared to conventional all-metal SVs, the proposed 2DEG-based SV potentially has the advantages of a higher MC ratio (of as high as 90%), external tenability, and less susceptibility to interfacial imperfections.