• 文献标题:   Andreev levels in a graphene-superconductor surface
  • 文献类型:   Article, Proceedings Paper
  • 作  者:   MANJARRES DA, HERRERA WJ, GOMEZ S
  • 作者关键词:   andreev level, specular andreev reflection, graphene
  • 出版物名称:   PHYSICA BCONDENSED MATTER
  • ISSN:   0921-4526 EI 1873-2135
  • 通讯作者地址:   Univ Nacl Colombia
  • 被引频次:   2
  • DOI:   10.1016/j.physb.2009.06.087
  • 出版年:   2009

▎ 摘  要

In order to consider the Dirac-like spectrum of graphene we employ the Bogoliubov de Gennes-Dirac formalism to determine the quasiparticle Andreev levels in an NS surface (normal-superconductor). The normal region is characterized by a width L while the superconducting region is semi-infinite and both regions are made of doped graphene. The quasiparticle energy spectrum is originated by the Andreev reflections that occur in the NS interface. It is shown that this spectrum depends on the width of the normal region and the Fermi energy in each region. When the Fermi energy in the normal metal is lower than the gap of the superconductor region, the spectrum is affected by specular Andreev reflections. The equation that is obtained to find the spectrum is very general and we solve it for some particular cases. We find that the energy spectrum oscillates when the Fermi energy in graphene is changed. Finally we obtain under some approximations an equation for the energy spectrum which is similar in structure as those obtained for an INS conventional junction. (C) 2009 Elsevier B.V. All rights reserved.