自旋场效应晶体管中隧道磁阻的势垒相关反转效应

Barrier-dependent tunneling magnetoresistance reversal effect in spin field effect transistors

考虑自旋场效应晶体管中Rashba自旋轨道相互作用和自旋输运量子相干性,研究了势垒强度对自旋场效应晶体管的自旋相关量子输运的影响.研究发现,势垒强度较低时,隧道结电导随Rashba自旋轨道相互作用强度的变化呈现明显的振荡现象,势垒强度较高时,电导表现出明显的势垒相关"电导开关"现象.当势垒强度逐渐增强时,平行结构电导呈现出单调下降趋势,而反平行结构电导产生波动,这种波动导致该隧道磁阻也随势垒强度的变化表现出振荡现象,且在合适的准一维电子气厚度情况下隧道磁阻值可以产生正负反转,这个效应将会在基于自旋的电子器件信息的存储上获得应用.

Considering Rashba spin orbit interaction and spin quantum transport in the spin field effect transistor, we study the influence of the barrier strength on the spin coherence transport in spin field effect transistors. It is found that when the barrier strength is weak, the tunneling junction conductance exhibits oscillatory phenomenon obviously with increasing Rashba spin orbit interaction strength. The conductance exhibites barrier-dependent ＂conductive switching effect＂ as the barrier strength increases. When the barrier strength gradually increases, parallel conductance exhibits a monotonicall decreasing trend, while the anti-parallel conductance fluctuates, and such a fluctuation leading to the tunneling magnetoresistance also exhibits oscillatory phenomenon with the variation of barrier strength. For a suitable thickness of quasi one-dimensional electron gas, the tunneling magnetoresistance value can produce positive and negative inversion, and the effect will shed light on the application of spin information storage electronic device.