石墨烯中选择性增强Kane-Mele型自旋-轨道相互作用  

Selective enhancement of Kane Mele-type spin-orbit interaction in graphene

作　　者：白占斌 王锐[1] 周亚洲 吴天如[3] 葛建雷 李晶 秦宇远 费付聪 曹路 王学锋[5] 王欣然 张帅 孙力玲[2] 宋友 宋凤麒 Bai Zhan-Bin;Wang Rui;Zhou Ya-Zhou;Wu Tian-Ru;Ge Jian-Lei;Li Jing;Qin Yu-Yuan;Fei Fu-Cong;Cao Lu;Wang Xue-Feng;Wang Xin-Ran;Zhang Shuai;Sun Li-Ling;Song You;Song Feng-Qi(Collaborative Innovation Center of Advanced Microstructures,National Laboratory of Solid State Microstructures,School of Physics,Nanjing University,Nanjing 210093,China;Beijing National Laboratory for Condensed Matter Physics,Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China;State Key Laboratory of Functional Materials for Informatics,Shanghai Institute of Microsystem and Information Technology,Chinese Academy of Sciences,Shanghai 200050,China;Collaborative Innovation Center of Advanced Microstructures,State Key Laboratory of Coordination Chemistry,School of Chemistry and Chemical Engineering,Nanjing University,Nanjing 210093,China;Collaborative Innovation Center of Advanced Microstructures,National Laboratory of Solid State Microstructures,School of Electronic Science and Engineering,Nanjing University,Nanjing 210093,China)

机构地区：[1]南京大学物理学院,固体微结构国家重点实验室,人工微结构科学与技术协同创新中心,南京210093 [2]中国科学院物理研究所,北京凝聚态物理国家研究中心,北京100190 [3]中国科学院上海微系统与信息技术研究所,信息功能材料国家重点实验室,上海200050 [4]南京大学化学化工学院,配位化学国家重点实验室,人工微结构科学与技术协同创新中心,南京210093 [5]南京大学电子科学与工程学院,固体微结构国家重点实验室,人工微结构科学与技术协同创新中心,南京210093

出　　处：《物理学报》2022年第6期257-263,共7页Acta Physica Sinica

基　　金：国家重点研发计划(批准号:2018YFA0306004);国家自然科学基金(批准号:U1732273,U1732159,12025404,11904166,11904165,61822403,11874203,11834006,91622115,11522432,11574217,21571097)资助的课题.

摘　　要：增强石墨烯中的自旋-轨道相互作用可能实现无耗散的量子自旋霍尔器件,这需要在石墨烯样品中引入独特的Kane-Mele型自旋-轨道相互作用,并保持较高的迁移率.然而,对石墨烯的外在修饰往往会引入“外禀型”Rashba自旋-轨道相互作用,会破坏可能存在的拓扑态,并带来一定程度的杂质散射,降低样品迁移率.在石墨烯表面修饰EDTA-Dy分子后,载流子迁移率得到了提高,并且可以看到显著的量子霍尔电导平台.其弱局域化效应相比被修饰之前得到了抑制,这意味石墨烯中可能引入了内禀的Kane-Mele型自旋-轨道相互作用,增强了Elliot-Yafet型电子自旋弛豫机制.进一步通过矢量磁体磁阻测量,发现该分子覆盖在石墨烯上后造成了石墨烯微弱的涟漪,这种涟漪引起的弯曲声子效应模拟了Kane-Mele型自旋-轨道相互作用.In order to enhance the spin orbit interaction(SOI)in graphene for seeking the dissipationless quantum spin Hall devices,unique Kane-Mele-type SOI and high mobility samples are desired.However,the common external modification of graphene often introduces“extrinsic”Rashba-type SOI,which will destroy the possible topological state,bring a certain degree of impurity scattering and reduce the sample mobility.Here we show that by the EDTA-Dy molecule dressing,the carrier mobility is even improved,and the quantum Hall plateaus are observed more clearly.The Kane-Mele type SOI is mimicked after dressing,which is evidenced by the suppressed weak localization at equal carrier densities and simultaneous Elliot-Yafet spin relaxation.This is attributed to the spin-flexural phonon coupling induced by the enhanced graphene ripples,as revealed by the in-plane magnetotransport measurement.

关 键 词：石墨烯 自旋-轨道相互作用 弯曲声子 弱局域化 

分 类 号：TQ127.11[化学工程—无机化工] O469[理学—凝聚态物理]