• 文献标题:   Overdoping Graphene Beyond the van Hove Singularity
  • 文献类型:   Article
  • 作  者:   ROSENZWEIG P, KARAKACHIAN H, MARCHENKO D, KUSTER K, STARKE U
  • 作者关键词:  
  • 出版物名称:   PHYSICAL REVIEW LETTERS
  • ISSN:   0031-9007 EI 1079-7114
  • 通讯作者地址:   Max Planck Inst Festkorperforsch
  • 被引频次:   0
  • DOI:   10.1103/PhysRevLett.125.176403
  • 出版年:   2020

▎ 摘  要

At very high doping levels the van Hove singularity in the pi* band of graphene becomes occupied and exotic ground states possibly emerge, driven by many-body interactions. Employing a combination of ytterbium intercalation and potassium adsorption, we n dope epitaxial graphene on silicon carbide past the pi* van Hove singularity, up to a charge carrier density of 5.5 x 10(14) cm(-2). This regime marks the unambiguous completion of a Lifshitz transition in which the Fermi surface topology has evolved from two electron pockets into a giant hole pocket. Angle-resolved photoelectron spectroscopy confirms these changes to be driven by electronic structure renormalizations rather than a rigid band shift. Our results open up the previously unreachable beyond-van-Hove regime in the phase diagram of epitaxial graphene, thereby accessing an unexplored landscape of potential exotic phases in this prototype two-dimensional material.