• 文献标题:   Imaging Graphene Moire Superlattices via Scanning Kelvin Probe Microscopy
  • 文献类型:   Article
  • 作  者:   YU JX, GIRIDHARAGOPAL R, LI YH, XIE KC, LI JY, CAO T, XU XD, GINGER DS
  • 作者关键词:   moire superlattice, abab/abca stacked graphene, scanning kelvin probe microscopy, local surface potential, work function
  • 出版物名称:   NANO LETTERS
  • ISSN:   1530-6984 EI 1530-6992
  • 通讯作者地址:  
  • 被引频次:   8
  • DOI:   10.1021/acs.nanolett.1c00609 EA MAR 2021
  • 出版年:   2021

▎ 摘  要

Moire superlattices in van der Waals heterostructures are gaining increasing attention because they offer new opportunities to tailor and explore unique electronic phenomena. Using a combination of lateral piezoresponse force microscopy (LPFM) and scanning Kelvin probe microscopy (SKPM), we directly correlate ABAB and ABCA stacked graphene with local surface potential. We find that the surface potential of the ABCA domains is similar to 15 mV higher (smaller work function) than that of the ABAB domains. First-principles calculations show that the different work functions between ABCA and ABAB domains arise from the stacking-dependent electronic structure. Moreover, while the moire superlattice visualized by LPFM can change with time, imaging the surface potential distribution via SKPM appears more stable, enabling the mapping of ABAB and ABCA domains without tip-sample contact-induced effects. Our results provide a new means to visualize and probe local domain stacking in moire ' superlattices along with its impact on electronic properties.