Topological aspects of π phase winding junctions in superconducting wires. (24th September 2015)

• Record Type: Journal Article
• Authors: Spånslätt, Christian; Ardonne, Eddy; Budich, Jan Carl; Hansson, T H
• Is Part Of: Journal of physics. Volume 27:Number 40(2015)
• Publication Date: 2015-09-24
• Subjects: topological superconductivity -- Kitaev wire model -- Josephson junction; Condensed matter -- Periodicals; Matière condensée -- Périodiques; Vaste stoffen; Vloeistoffen; Natuurkunde; Electronic journals; Computer network resources; 530.4105
• DOI: 10.1088/0953-8984/27/40/405701
• Languages: English
• ISSNs: 0953-8984

Abstract

Abstract: We theoretically investigate Josephson junctions with a phase shift of π in various proximity induced one-dimensional superconductor models. One of the salient experimental signatures of topological superconductors, namely the fractionalized periodic Josephson effect, is closely related to the occurrence of a characteristic zero energy bound state in such junctions. We make a detailed analysis of a more general type of π -junctions coined 'phase winding junctions' where the phase of the order parameter rotates by an angle π while its absolute value is kept finite. Such junctions have different properties, also from a topological viewpoint, and there are no protected zero energy modes. We compare the phenomenology of such junctions in topological ( p -wave) and trivial ( s -wave) superconducting wires, and briefly discuss possible experimental probes. Furthermore, we propose a topological field theory that gives a minimal description of a wire with defects corresponding to π -junctions. This effective theory is a one-dimensional version of similar theories describing Majorana bound states in half-vortices of two-dimensional topological superconductors.