HgMnTe单晶光致磁化效应的红外调制光谱研究

Using external field to control spin-splitting is a key issue in semiconductor spintronics. For a long time, people focus on spin regulation by electricity method, but the research based on optical method is relative lack. Photoinduced magnetization of (diluted) magnetic semiconductor provides a attractive solution that using light field to achieve the regulation of spin polarization. In the past, people just studied the photoinduced magnetization of HgMnTe by magnetic method, however, optical result is blank to date and its microscopic mechanism is also not clear. This is due to: 1) optical signal carrying photoinduced magnetization information is located in the infrared band, which is difficult for conventional spectroscopic technique to detect; 2) shallow impurity luminescence is a large disturbance in distinguishing the fingerprint of photoinduced magnetization - Zeeman splitting of band-to-band transition. We propose a novel method to study the photo induced magnetization in p-type Hg1-xMnxTe single crystal that utilizes infrared magneto-optical modulation technique and magnetic transport mechanism. We focus on how Mn composition, acceptor concentration, photo-generated carrier density and temperature might affect the photo-induced magnetization, and analyze the magneto-optic experiment result using eight-band k*p perturbation theory. These results will shed light on the understanding of microscopic mechanism of photo-induced magnetization in p-type HgMnTe, pave the road to realize the ultimate goal of optical manipulation of electronic spin, and advance the studies of semiconductor spintronics.

利用外场调控自旋分裂是半导体自旋电子学当前的核心问题。长时间来，人们专注于用电学方法实现自旋调控，而基于光学方法的研究则相对缺乏。(稀)磁性半导体的光致磁化效应提供了基于光场调控自旋极化的诱人方案。过去，人们仅用磁学方法研究了HgMnTe的光致磁化效应，而光学研究结果迄今空白，且微观机理不清晰。其光学研究难点主要有：一、携带光致磁化效应信息的光学信号位于红外波段，传统光谱技术难以清晰检测；二、浅杂质发光对分辨光致磁化效应指纹—带带Zeeman分裂的干扰大。.本项目创新点：综合运用红外调制磁光技术和磁输运方法研究p型Hg1-xMnxTe单晶的光致磁化效应，重点关注Mn组分、受主浓度、光生载流子浓度和温度对光致磁化效应的影响规律，并根据磁性8带k•p微扰方法分析磁光实验结果。藉此澄清p型HgMnTe单晶光致磁化效应的微观机理，为实现光学调控自旋的目标提供支持，助推半导体自旋电子学的发展。

发展探测与调控半导体自旋的实验方法对检验凝聚态物理理论、提升自旋器件的性能具有重要意义。长时间来，人们专注于用电学方法实现自旋调控，而基于光学方法的研究则相对缺乏。(稀)磁性半导体的光致磁化效应提供了基于光场调控自旋极化的诱人方案。过去，人们仅用磁学方法研究了HgMnTe的光致磁化效应，而光学研究结果迄今空白，且微观机理不清晰。其光学研究难点主要有：一、携带光致磁化效应信息的光学信号位于红外波段，传统光谱技术难以清晰检测；二、浅杂质发光对分辨光致磁化效应指纹—带带Zeeman分裂的干扰大。.本项目：综合运用红外调制磁光技术和磁输运方法研究了p型Hg1-xMnxTe单晶的光致磁化效应，并对不同Mn组分、受主浓度、光生载流子浓度和温度对光致磁化效应的影响进行了系统分析。获得以下主要进展和结果：.(1) 首次实现两路并发探测调制PL光谱技术，并成功应用于HgMnTe单晶的光致磁化效应研究。.(2) 根据实验结果，并结合磁性8带k•p微扰方法的模型计算数据，得出HgMnTe单晶光致磁化效应的微观机理为渗流机制和受主-束缚磁极化子共同作用。.为实现光学调控自旋的目标提供了支持，助推半导体自旋电子学的发展。

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