Josephson effect in spin-singlet superconductor/ferromagnetic insulator/spin-triplet superconductor junctions with helical p-wave states

¹ School of Science, Qingdao Technological University - Qingdao 266520, China
² School of Physics, University of Chinese Academy of Sciences - Beijing 100049, China

^(a) chengqiang07@mails.ucas.ac.cn
^(b) biaojin@ucas.ac.cn

Received: 9 October 2015
Accepted: 14 January 2016

Abstract

We study the Josephson effect in spin-singlet superconductor/helical p-wave superconductor junctions with a ferromagnetic barrier using the quasiclassical Green function method. It is found that both sin ϕ-type and cos ϕ-type current-phase relations always exist, irrespective of the gap symmetries in superconductors. The indispensable condition for the sin ϕ-type and cos ϕ-type current is that the magnetization must have a component parallel to the crystallographic a- or b-axis, which is distinct from the case of the p-wave superconductor described by a d-vector with a uniform direction. The relation between the condition and the symmetries of the gap functions is analysed. We investigate in detail the symmetries and the sign reversal of the Josephson current when the magnetization is rotated.