GaAs高过超能量态电子自旋相干动力学研究

滕利华， 王霞， 牟丽君

(青岛科技大学  数理学院, 山东 青岛 266061)

摘要： 研究了96 K低温下、本征GaAs高过超能量态电子自旋相干动力学的浓度依赖，发现当光子能量为157 eV, 载流子浓度增大至265×1017cm-3时电子自旋相干量子拍的相位翻转180°。 理论计算表明量子拍的相位翻转为区分轻、重空穴系统提供了重要依据，当载流子浓度大于26×1017cm-3时，量子拍的振幅主要起源于重空穴价带导带跃迁，当载流子浓度小于26×1017cm-1时，量子拍的振幅主要起源于轻空穴价带导带跃迁。因而，分别在轻空穴价带导带系统和重空穴价带导带系统实验测量电子自旋相干动力学成为可能，实验数据表明在轻空穴价带导带系统测得的电子自旋相干弛豫时间明显大于在重空穴价带导带系统测得的电子自旋相干弛豫时间。

 关键词： 圆偏振光抽运探测光谱； 自旋相干动力学； 浓度依赖； GaAs

 中图分类号： O 473     文献标志码: A

 Spin Coherence Dynamics of Electron with High Excess Energy in GaAs

 TENG Lihua, WANG Xia, MU Lijun

(College of Mathematics and Physics, Qingdao University of Science and Technology, Qingdao 266061，China)

Abstract: Timeresolved circularly polarized pumpprobe spectroscopy is used to study the carrier density dependence of the electronspin coherence dynamics in intrinsic GaAs at 96 K. It is found that the phase of the quantum beats is altered by 180° when the carrier density is increased to 265×1017cm-3 with the photon energy of 157 eV. Theoretical calculation shows that the phase reversal of quantum beats provides the key information to distinguish the heavy hole and light hole systems, when the carrier density is larger than 26×1017cm-3, the quantum beats mainly originates from the heavy hole valance bandconduction band transitions, otherwise, the quantum beats mainly originates from the light hole valance bandconduction band transitions, thus spin coherence dynamics in heavy hole valance band and light hole valance bandconduction band systems can be measured separately, the experimental data shows that spin coherence relaxation time measured in heavy hole valance bandconduction band system is larger than thatmeasured in light hole valance bandconduction band system.

 Key words: circularly polarized pumpprobe spectroscopy; spin coherence dynamics; density dependence; GaAs

 收稿日期： 20130923

 基金项目：  国家自然科学基金项目(11274189, 11104162);山东省自然科学基金青年基金项目(ZR2012AQ006);青岛市科技计划项目(112431jch，1424101jch).

 作者简介：  滕利华 (1980—)，男，副教授，博士.