Electrical control of ballistic spin-dependent conductance through magneto-electric barriers in the 2D-electron gas of GaAs heterostructure

摘要

It has been conceived and proven experimentally [1] that spin-dependent conductance of electron can be achieved across semiconductor as well as non-magnetic materials. Spin-polarized current has been shown to switch [2] the magnetization of thin film magnetic materials, at reasonably low current density of 10{sup}7Acm{sup}(-2). In this article, we will investigate the method of resonant tunneling [3,4] through a double-pair potential barrier to induce spin-polarized current in the 2D-electron gas (2DEG) of a high-electron-mobility-transistor (HEMT) heterostructure. We focus on the effect of electrical barriers which can be conveniently established by applying electrical voltage to the ferromagnetic gates of the HEMT device as shown in Fig.1. We found that electrical potential could be utilized here to control not only the spin current, but also the charge current. The pre-requisite is symmetrical magnetic potential (Ay) must first be established along the 2DEG x-axis by magnetizing the ferromagnetic gates accordingly. Subsequent application of asymmetrical electric potential turns on spin current, while symmetrical potential turns off spin current. However, charge current persists even in the absence of spin current. Increasing the strength of the symmetrical electric potential switches off both charge and spin current.