• 文献标题:   Charged skyrmions and topological origin of superconductivity in magic-angle graphene
  • 文献类型:   Article
  • 作  者:   KHALAF E, CHATTERJEE S, BULTINCK N, ZALETEL MP, VISHWANATH A
  • 作者关键词:  
  • 出版物名称:   SCIENCE ADVANCES
  • ISSN:   2375-2548
  • 通讯作者地址:  
  • 被引频次:   72
  • DOI:   10.1126/sciadv.abf5299
  • 出版年:   2021

▎ 摘  要

Topological solitons, a class of stable nonlinear excitations, appear in diverse domains as in the Skyrme model of nuclear forces. Here, we argue that similar excitations play an important role in a remarkable material obtained on stacking and twisting two sheets of graphene. Close to a magic twist angle, insulating behavior is observed, which gives way to superconductivity on doping. Here, we propose a unifying description of both observations. A symmetry breaking condensate leads to the ordered insulator, while topological solitons in the condensate-skyrmions-are shown to be charge 2e bosons. Condensation of skyrmions leads to a superconductor, whose physical properties we calculate. More generally, we show how topological textures can mitigate Coulomb repulsion and provide a previously unexplored route to superconductivity. Our mechanism not only clarifies why several other moire materials do not show superconductivity but also points to unexplored platforms where robust superconductivity is anticipated.