Bandgap opening in MoTe2 thin flakes induced by surface oxidation

作     者：Yuan Gan Jiyuan Liang Chang-woo Cho Si Li Yanping Guo Xiaoming Ma Xuefeng Wu Jinsheng Wen Xu Du Mingquan He Chang Liu Shengyuan A.Yang Kedong Wang Liyuan Zhang Yuan Gan;Jiyuan Liang;Chang-woo Cho;Si Li;Yanping Guo;Xiaoming Ma;Xuefeng Wu;Jinsheng Wen;Xu Du;Mingquan He;Chang Liu;Shengyuan A.Yang;Kedong Wang;Liyuan Zhang

作者机构：National Laboratory of Solid State Microstructures and Department of PhysicsNanjing UniversityNanjing210093China Department of PhysicsSouthern University of Science and TechnologyShenzhen518055China School of Physics and ElectronicsHunan Normal UniversityChangsha410081China Research Laboratory for Quantum MaterialsSingapore University of Technology and DesignSingapore487372Singapore Beijing National Laboratory for Condensed Matter Physics and Institute of PhysicsChinese Academy of SciencesBeijing100190China Department of Physics and AstronomyStony Brook UniversityStony BrookNY11794USA Chongqing Key Laboratory of Soft Condensed Matter Physics and Smart MaterialsCollege of PhysicsChongqing UniversityChongqing401331China 

出 版 物：《Frontiers of physics》 (物理学前沿（英文版）)

年 卷 期：2020年第15卷第3期

页      面：105-111页

核心收录：

学科分类：081702[工学-化学工艺] 08[工学] 0817[工学-化学工程与技术] 0704[理学-天文学] 0702[理学-物理学] 

基　　金：The work was supported by the Guangdong Innovative and Entrepreneurial Research Team Program,China(Grant No.2016ZT06D348) the National Natural Science Foundation of China(Grant No.11874193) the Shenzhen Fundamental Subject Research Program,China(Grant No.JCYJ20170817110751776).K.D.W.acknowledges support from the National Natural Science Foundation of China(Grant No.11574128).X.D.acknowledges support from NSF under award DMR-1808491 

主　　题：two-dimensional materials metal-insulator transition layered transition metal dichalcogenides(TMDs) surface oxidation 

摘      要：Recently,the layered transition metal dichalcogenide 1T′-MoTe2 has generated considerable interest due to their superconducting and non-trivial topological ***,we present a systematic study on 1T′-MoTe2 single-crystal and exfoliated thin-flakes by means of electrical transport,scanning tunnelling microscope(STM)measurements and band structure *** a bulk sample,it exhibits large magneto-resistance(MR)and Shubnikov–de Hass oscillations inρxx and a series of Hall plateaus inρxy at low ***,the MoTe2 thin films were intensively investigated with thickness *** samples,without encapsulation,an apparent transition from the intrinsic metallic to insulating state is observed by reducing *** such thin films,we also observed a suppression of the MR and weak anti-localization(WAL)*** attributed these effects to disorders originated from the extrinsic surface chemical reaction,which is consistent with the density functional theory(DFT)calculations and in-situ STM *** contrast to samples without encapsulated protection,we discovered an interesting superconducting transition for those samples with hexagonal Boron Nitride(h-BN)film *** results indicate that the metallic or superconducting behavior is its intrinsic state,and the insulating behavior is likely caused by surface oxidation in few layer 1T’-MoTe2 flakes.