Zigzag边纳米石墨带超导结中的可控0-π相变  

Controllable 0-π transition in a zigzag superconducting graphene-nanoribbon junction

作　　者：梁奇锋[1,2] 余勇[1] 王强华[1] 董锦明[1] 

机构地区：[1]南京大学物理系固体微结构国家实验室计算凝聚态物理组,南京210093 [2]绍兴文理学院物理系,绍兴312000

出　　处：《物理》2009年第2期100-104,共5页Physics

基　　金：国家重点基础研究发展计划(批准号:2004CB619004,2006CB921803);国家自然科学基金(批准号:90503012,10874067)资助项目

摘　　要：文章作者利用实空间格林函数方法研究了超导体-zigzag边纳米石墨带-超导体(SGS)约瑟夫森结中的超导输运行为.结果发现:(1)通过一个外加横向电场可以使该超导结的超流方向发生翻转,即发生超导0-π相变;(2)通过改变纳米石墨带的长度或者其上的门电压,同样也可以使它发生0-π相变.由于可以用外电场方便地控制该超导结0-π相变的发生,使得它有可能在未来的量子计算以及超导电子学中发挥巨大的作用.The supercurrent in a Josephson junction composed of a zigzag-edged graphene nanoribbon （ZGNR） lying between two superconducting leads [ superconductor-graphene-superconductor （ SGS ） junction ] has been studied by the Green＇s function method. It is found that applying a small transverse electric field can reverse the supercurrent direction, leading to a so - called O-π phase transition. This transition can also happen periodically with a given change in the ZGNR＇s length, and, more importantly, can be easily and electrically controllable by a gate voltage, which is not possible in conventional superconducting π junctions and makes the SGS junction very promising for future application in superconducting electronics, as well as in quantum information and computation.

关 键 词：纳米材料 超导电性 约瑟夫森效应 O-π相变 

分 类 号：O511[理学—低温物理]