Controllable 0-pi transition in a superconducting graphene-nanoribbon junction.
The supercurrent in a Josephson junction composed of the 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 a small transverse electric field applied on the ZGNR can reverse the supercurrent direction, leading to a so-called 0-pi phase transition. The 0-pi phase transition can happen periodically with a change in the ZGNR's length, and, more importantly, can be easily and electrically controllable by a gate voltage, which is absent in the conventional superconducting pi junction and would make the SGS junction very promising for future application in superconducting electronics, as well as quauntum information and computation.
Liang
Qifeng
Q
Group of Computational Condensed Matter Physics, National Laboratory of Solid State Microstructures and Department of Physics, Nanjing University, Nanjing 210093, People's Republic of China.
Yu
Yong
Y
Wang
Qianghua
Q
Dong
Jinming
J