Tunable ground states in helical p-wave Josephson junctions. (3rd June 2016)

• Record Type: Journal Article
• Authors: Cheng, Qiang; Zhang, Kunhua; Yu, Dongyang; Chen, Chongju; Zhang, Yinhan; Jin, Biao
• Is Part Of: Superconductor science & technology. Volume 29:Number 7(2016:Jul.)
• Publication Date: 2016-06-03
• Subjects: Josephson junctions -- helical superconductivity -- ferromagnetism; Superconductivity -- Periodicals; Superconductors -- Periodicals; 537.623
• DOI: 10.1088/0953-2048/29/7/075010
• Languages: English
• ISSNs: 0953-2048

Abstract

Abstract: We study new types of Josephson junctions composed of helical p -wave superconductors with k x x ˆ ± k y y ˆ and k y x ˆ ± k x y ˆ -pairing symmetries using quasi-classical Green's functions with generalized Riccati parametrization. The junctions can host rich ground states: π phase, 0 + π phase, φ 0 phase and φ phase. The phase transition can be tuned by rotating the magnetization in the ferromagnetic interface. We present the phase diagrams in the parameter space formed by the orientation of the magnetization or by the magnitude of the interfacial potentials. The selection rules for the lowest order current which are responsible for the formation of the rich phases are summarized from the current-phase relations based on the numerical calculation. We construct a Ginzburg–Landau type of free energy for the junctions withd -vectors and the magnetization, which not only reveals the interaction forms of spin-triplet superconductivity and ferromagnetism, but can also directly lead to the selection rules. In addition, the energies of the Andreev bound states and the novel symmetries in the current-phase relations are also investigated. Our results are helpful both in the prediction of novel Josephson phases and in the design of quantum circuits.