• 文献标题:   Two-gap superconductivity in heavily n-doped graphene: Ab initio Migdal-Eliashberg theory
  • 文献类型:   Article
  • 作  者:   MARGINE ER, GIUSTINO F
  • 作者关键词:  
  • 出版物名称:   PHYSICAL REVIEW B
  • ISSN:   1098-0121 EI 1550-235X
  • 通讯作者地址:   SUNY Binghamton
  • 被引频次:   32
  • DOI:   10.1103/PhysRevB.90.014518
  • 出版年:   2014

▎ 摘  要

Graphene is the only member of the carbon family from zero-to three-dimensional materials for which superconductivity has not been observed yet. At this time, it is not clear whether the quest for superconducting graphene is hindered by technical challenges, or else by the fluctuation of the order parameter in two dimensions. In this area, ab initio calculations are useful to guide experimental efforts by narrowing down the search space. In this spirit, we investigate from first principles the possibility of inducing superconductivity in doped graphene using the fully anisotropic Migdal-Eliashberg theory powered by Wannier-Fourier interpolation. To address a best-case scenario, we consider both electron and hole doping at high carrier densities so as to align the Fermi level to a van Hove singularity. In these conditions, we find superconducting gaps of s-wave symmetry, with a slight anisotropy induced by the trigonal warping, and, in the case of n-doped graphene, an unexpected two-gap structure reminiscent of MgB2. Our Migdal-Eliashberg calculations suggest that the observation of superconductivity at low temperature should be possible for n-doped graphene at carrier densities exceeding 10(15) cm(-2).