自旋轨道耦合与磁场对电子透射率的影响

Influence of Spin-orbit Coupling and Magnetic Field on Electronic Transmissivity

研究了铁磁体-半导体-铁磁体(F/S/F)准一维系统中电子的透射率.得到如下结论:1)改变作用在2铁磁体上磁场方向角ρ和θ,电子透射率在满足ρ+θ=(2n+1)π时最小,ρ+θ=2nπ时最大(其中n=1,2,3,…).2)δ势垒起到了延迟电子共振隧穿峰到来的作用.3)改变半导体中电子的Rashba自旋轨道耦合常数α会使电子透射产生非周期性共振隧穿现象,并且随着a值的增大相邻共振隧穿峰的间距有增大的趋势.4)半导体长度的改变虽然不会使相邻共振隧穿峰的间距改变,但会使共振隧穿峰值发生变化.

Electronic transmissivity is studied in the quasi one-dimensional system of Ferromagnet-Semicon- ductor-Ferromagnet （F/S/F）. Thus the following conclusions are drawn： 1） The direction tangles ρ and θ of magnetic field in the ferromagnetic electrodes could change electronic transrnissivity, which is minimum if ρ＋ θ = （2n ＋ 1）π and maximum if ρ ＋ θ=2nπ（n = 1,2,3,…）.2） δ potential at the interface plays a role in postpon- ing reach of electronic resonant-tunnelling peaks. 3） Changing Rashba spin-orbit coupling constant a can make transmission electrons appear aperiodic resonant-tunnelling phenomenon, and the distance between two adjacent resonant-tunnelling peaks tends to increase with growing of parameter a, in other words, the bigger the parameter a is,the longer the distance between two adjacent resonant-tunnelling peaks is（in the study, Rashba spin-orbit coupling constant a is changed through changing parameter a ）. 4） The length d of semiconductor could not make the distance between two adjacent resonant-tunnelling peaks change, but would make resonant-tunnelling peak value change.