Strongly anharmonic current-phase relation in ballistic graphene Josephson junctions

Annica M. Black-Schaffer; Jacob Linder

doi:10.1103/PhysRevB.82.184522

← Back to search

Strongly anharmonic current-phase relation in ballistic graphene Josephson junctions

Annica M. Black-Schaffer, Jacob Linder

DOI 10.1103/PhysRevB.82.184522 · Physical Review B

T1

Active bibliographic source — not scientific approval

Bibliographic access preserves source history; it does not approve extracted materials or validate reported claims. Review warnings on each occurrence separately.

Abstract

Motivated by a recent experiment directly measuring the current-phase relation (CPR) in graphene under the influence of a superconducting proximity effect, we here study the temperature dependence of the CPR in ballistic graphene superconductor-normal metal-superconductor (SNS) Josephson junctions within the self-consistent tight-binding Bogoliubov-de Gennes (BdG) formalism. By comparing these results with the standard Dirac-BdG method, where rigid boundary conditions are assumed at the S∣N interfaces, we show on a crucial importance of both proximity effect and depairing by current for the CPR. The proximity effect grows with temperature and reduces the skewness of the CPR toward the harmonic result. In short junctions (L<ξ) current depairing is also important and gives rise to a critical phase ϕc<π/2 over a wide range of temperatures and doping levels.