Colossal structural distortion and interlayer-coupling suppression in a van der Waals crystal induced by atomic vacancies  

作　　者：Liangguang Jia Fei Gao Yu Zhang Yaoyao Chen Baofei Hou Zeping Huang Quanzhen Zhang Xu Wu Liwei Liu Shiwu Gao Mads Brandbyge Hong-Jun Gao Yeliang Wang 

机构地区：[1]School of Integrated Circuits and Electronics,MIIT Key Laboratory for Low-Dimensional Quantum Structure and Devices,Beijing Institute of Technology,Beijing 100081,China [2]Center for Nanostructured Graphene,Department of Physics,Technical University of Denmark,Kongens Lyngby DK-2800,Denmark [3]Advanced Research Institute of Multidisciplinary Sciences,Beijing Institute of Technology,Beijing 100081,China [4]Beijing Computational Science Research Center,Beijing 100193,China [5]Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China

出　　处：《Nano Research》2023年第4期5715-5720,共6页纳米研究（英文版）

基　　金：supported by National Natural Science Foundation of China(Nos.92163206,61725107,12274026,61971035,62271048,11934003,21961132023,and U1930402);National Key Research and Development Program Program of China(Nos.2020YFA0308800,2021YFA1400100,2022YFA1402502,and 2022YFA1402602);Beijing Natural Science Foundation(No.Z190006);China Postdoctoral Science Foundation(No.2021M700407),Villum Fonden(No.00013340),and the Danish Research Foundation(No.DNRF103)。

摘　　要：The interlayer coupling in van der Waals(vdW)crystals has substantial effects on the performance of materials.However,an indepth understanding of the microscopic mechanism on the defect-modulated interlayer coupling is often elusive,owing partly to the challenge of atomic-scale characterization.Here we report the native Se-vacancies in a charge-density-wave metal 2HNbSe2,as well as their influence on the local atomic configurations and interlayer coupling.Our low-temperature scanning tunneling microscopy(STM)measurements,complemented by density functional theory calculations,indicate that the Sevacancies in few-layer NbSe2 can generate obvious atomic distortions due to the Jahn-Teller effect,thus breaking the rotational symmetry on the nanoscale.Moreover,these vacancies can locally generate an in-gap state in single-layer NbSe2,and more importantly,lead to a colossal suppression of interlayer coupling in the bilayer system.Our results provide clear structural and electronic fingerprints around the vacancies in vdW crystals,paving the way for developing functional vdW devices.

关 键 词：atomic vacancies structural distortion interlayer coupling scanning tunneling microscopy 

分 类 号：TB383[一般工业技术—材料科学与工程]