11月10日 中科院半导体所骆军委研究员报告：Spin-orbit coupling in semiconductors

报告题目：Spin-orbit coupling in semiconductors

时间：11月10日（周四）下午4:00

地点：唐楼A313

 

 

报告摘要及报告人简介：

Spin-orbit coupling in semiconductors

 

Jun-Wei Luo （骆军委）

State key laboratory of superlattices and microstructures, Institute of Semiconductors, Chinese Academy of Sciences

 

Abstract

Spin-orbit coupling is a key property of semiconductors to explore spintronics without external magnetic field. It can induce spin polarization, acting like an effective magnetic field, in nonmagnetic 3D crystals when the inversion symmetry is broken, as manifested by the bulk Rashba and Dresselhaus effects. We establish that these spin-polarization effects originate fundamentally from specific atomic site asymmetries, rather than, as generally accepted, from the asymmetry of the crystal space group. This understanding leads to the recognition that a previously overlooked hidden form of spin polarization should exist in centrosymmetric crystals. Although all energy bands must be doubly degenerate in centrosymmetric materials, we find that the two components of such doubly degenerate bands could have opposite polarizations, each spatially localized on one of the two separate sectors forming the inversion partners. We demonstrate such hidden spin polarizations in particular centrosymmetric crystals by first-principles calculations. This new understanding could considerably broaden the range of currently useful spintronic materials and enable the control of spin polarization by means of operations on the atomic scale. I will also present our recent works on novel Rashba spin-orbit coupling effects in one-dimensional nanowires.

 

References

［1］ X.W. Zhang, Q.H. Liu, Jun-Wei Luo*, A. Freeman, and Alex Zunger*, “Hidden spin polarization in inversion-symmetric bulk crystals”, Nature Physics 10, 387 (2014).

［2］ Jun-Wei Luo, Lijun Zhang, and Alex Zunger, “Absence of intrinsic spin splitting in 1D quantum wires of tetrahedral semiconductors”, Phys. Rev. B (Rapid. Comm.) 84 121303 (2011).

［3］ Jun-Wei Luo, A. N. Chantis, M. van Schilfgaarde, G. Bester, and A. Zunger, “Discovery of a Novel Linear-in-k Spin Splitting for Holes in the 2D GaAs/AlAs System”, Phys. Rev. Lett. 104, 066405 (2010).

［4］ Jun-Wei Luo, Gabriel Bester, and Alex Zunger, “Full-zone spin-splitting for electrons and holes in bulk GaAs and GaSb”, Phys. Rev. Lett. 102, 056405 (2009).

［5］ Jun-Wei Luo, Shu-Shen Li, and Alex Zunger, “Emergence of an upper bound to the electric field controlled Rashba spin splitting in InAs nanowires”, Phys. Rev. B (Rapid. Comm.) (under review).

［6］ Jun-Wei Luo, Shu-Shen Li, and Alex Zunger, “Abrupt saturation of the highly tunable Rashba spin-orbit coupling in one-dimensional holes”, manuscript in preparation.

 

 

骆军委，中国科学院半导体研究所研究员，半导体超晶格国家重点实验室副主任，中组部青年海外高层次人才计划获得者。2006年在中国科学院半导体研究所获得博士学位。2007－2014年在美国可再生能源国家实验室工作，先后担任博士后、永久职位科学家、资深科学家。2014年回国工作。研究领域为半导体物理与器件模拟, 在半导体自旋轨道耦合效应、硅基半导体信息功能材料理论设计和发展原子精度全量子力学器件模拟方法等领域开展了系统的研究，已在包括Nature子刊 (4篇)、Phys. Rev. Lett. (5篇)、JACS (1篇)、IEDM(1篇)、Energy & Env. Sci. (1篇)、Nano Lett. (7篇)等国际学术期刊上发表SCIE论文50余篇，被SCIE他引1000余次。多次在APS、ACS和E-MRS等国际重要会议做邀请报告和分会主席。