Enhancement of the Spin Accumulation at the Interface between a Spin-Polarized Tunnel Junction and a Semiconductor
Enhancement of the Spin Accumulation at the Interface between a Spin-Polarized Tunnel Junction and a Semiconductor
复制标题
DOI：
10.1103/physrevlett.102.036601
复制
发表时间：
2009-01-23
影响因子：
8.6
通讯作者：
Lemaitre, A.
中科院分区：
文献类型：
--
作者：
Tran, M.;Jaffres, H.;Lemaitre, A.
我们报告了具有电检测功能的 Co/Al(2)O(3)/GaAs 界面的自旋注入实验。对于 0.34 nA 中心点 mu m(-2) 的电流密度，施加横向磁场会在界面处产生高达 1.2 mV 的大电压降 Delta V。这代表自旋积累信号的显着增加，远高于通过铁磁体/半导体界面自旋注入的理论预测。这种增强与通过位于 Al(2)O(3)/GaAs 界面附近的局域态的顺序隧道过程一致。对于自旋极化载流子，这些态充当自旋寿命较长的累积层。考虑到载流子返回铁磁接触的自旋寿命和逃逸隧道时间的模型准确地再现了实验结果。
We report on spin injection experiments at a Co/Al(2)O(3)/GaAs interface with electrical detection. The application of a transverse magnetic field induces a large voltage drop Delta V at the interface as high as 1.2 mV for a current density of 0.34 nA center dot mu m(-2). This represents a dramatic increase of the spin accumulation signal, well above the theoretical predictions for spin injection through a ferromagnet/semiconductor interface. Such an enhancement is consistent with a sequential tunneling process via localized states located in the vicinity of the Al(2)O(3)/GaAs interface. For spin-polarized carriers these states act as an accumulation layer where the spin lifetime is large. A model taking into account the spin lifetime and the escape tunneling time for carriers traveling back into the ferromagnetic contact reproduces accurately the experimental results.