• 文献标题:   Direct observation of minibands in a twisted graphene/WS2 bilayer
  • 文献类型:   Article
  • 作  者:   ULSTRUP S, KOCH RJ, SINGH S, MCCREARY KM, JONKER BT, ROBINSON JT, JOZWIAK C, ROTENBERG E, BOSTWICK A, KATOCH J, MIWA JA
  • 作者关键词:  
  • 出版物名称:   SCIENCE ADVANCES
  • ISSN:   2375-2548
  • 通讯作者地址:   Aarhus Univ
  • 被引频次:   4
  • DOI:   10.1126/sciadv.aay6104
  • 出版年:   2020

▎ 摘  要

Stacking two-dimensional (2D) van der Waals materials with different interlayer atomic registry in a heterobilayer causes the formation of a long-range periodic superlattice that may bestow the heterostructure with properties such as new quantum fractal states or superconductivity. Recent optical measurements of transition metal dichalcogenide (TMD) heterobilayers have revealed the presence of hybridized interlayer electron-hole pair excitations at energies defined by the superlattice potential. The corresponding quasiparticle band structures, so-called minibands, have remained elusive, and no such features have been reported for heterobilayers composed of a TMD and another type of 2D material. We introduce a new x-ray capillary technology for performing microfocused angle-resolved photoemission spectroscopy with a spatial resolution of similar to 1 mu m, and directly observe minibands at certain twist angles in mini Brillouin zones (mBZs). We discuss their origin in terms of initial and final state effects by analyzing their dispersion in distinct mBZs.