(Ga,Mn)As中电流诱导自旋极化的磁光Kerr测量  

Observation of current-induced polarization in(Ga,Mn)As via magneto-optic Kerr measurement

作　　者：谷晓芳[1] 钱轩[1] 姬扬[1] 陈林[1] 赵建华[1] 

机构地区：[1]中国科学院半导体研究所超晶格国家重点实验室,北京100083

出　　处：《物理学报》2012年第3期442-448,共7页Acta Physica Sinica

基　　金：国家重点基础研究发展计划(批准号:2009CB929301);国家自然科学基金(批准号:10911130232)资助的课题~~

摘　　要：在GaAs吸收带边附近,利用磁光Kerr效应测量了(Ga,Mn)As和p-GaAs样品的电流诱导Kerr旋转谱和反射谱,两者都呈现出Lorentz曲线形状.电流诱导Kerr旋转角和反射率随着电流的增大而增大,Kerr角与电流的大小成正比关系,反射率与电流的平方成正比关系.(Ga,Mn)As的Kerr旋转角比p-GaAs的大了一个数量级,这说明Mn原子的掺杂使得电流诱导的自旋极化增强.另外,还测量了温度和入射光偏振方向对电流诱导Kerr旋转谱和反射谱的影响.发现随着温度的升高,Kerr谱和反射谱均向长波方向移动,这与GaAs带边随温度的变化是一致的.Current-induced Kerr rotation spectra and reflectivity spectra of（Ga,Mn）As and p-GaAs are measured in the absence of the magnetic field via magneto-optic Kerr effect around the energy gap.The dependences of the Kerr rotation and the reflectivity on the laser wavelength show Lorentzian profile.The Kerr rotation depends linearly on the current,and the reflectivity depends linearly on the square of the current.The Kerr rotation of p-GaAs is much weaker than that of the（Ga,Mn）As,which indicates that the doping of Mn enhances the current-induced spin polarization.The dependences of the Kerr rotation and the reflectivity on temperature are also measured,both showing red shifts of their Lorentzian peaks,a familiar behavior as the absorption edge of GaAs.In addition,we observe the dependence of the Kerr signal on the polarizational direction of the incident beam.

关 键 词：自旋电子学 稀磁半导体 电流诱导自旋极化 

分 类 号：O482.5[理学—固体物理]