Time-reversal symmetry and topology in one-dimensional Josephson junctions

Mellars, Ehren Axel (2018). Time-reversal symmetry and topology in one-dimensional Josephson junctions. University of Birmingham. Ph.D.

[img]
Preview
Mellars18PhD.pdf
Text - Accepted Version
Available under License All rights reserved.

Download (4MB) | Preview

Abstract

We explore the roles of topology and time-reversal symmetry in one-dimensional superconducting systems. Specifically, we examine junctions involving time-reversal-invariant topological superconductors, which are characterised by the emergence of zero-energy Majorana- Kramers pairs at their boundaries. For Josephson junctions composed of these superconductors, we obtain, through a scattering matrix technique valid in a regime where the junction length is much shorter than the superconducting coherence length, exact analytical and numerical results for the Josephson current in terms of a small number of independently measurable junction parameters. The current is found to have a number of prominent and robust features which indicate the underlying symmetries and the nontrivial topology inherent in these systems. The most remarkable of these features occurs in the form of switches in the Josephson current, where the sign of the current reverses as a consequence of crossings between energy levels in the subgap spectrum. By utilising a quantum master equation approach, we establish general conditions under which these switches manifest in relation to a phenomenological relaxation rate and a voltage applied across the junction. Our findings enable quantitative predictions for such junctions, potentially assisting in experimental directions regarding the detection of Majorana- Kramers pairs in mesoscopic Josephson systems.

Type of Work: Thesis (Doctorates > Ph.D.)
Award Type: Doctorates > Ph.D.
Supervisor(s):
Supervisor(s)EmailORCID
Béri, BenjjaminUNSPECIFIEDUNSPECIFIED
Licence: All rights reserved
College/Faculty: Colleges (2008 onwards) > College of Engineering & Physical Sciences
School or Department: School of Physics and Astronomy
Funders: None/not applicable
Subjects: Q Science > QC Physics
URI: http://etheses.bham.ac.uk/id/eprint/8739

Actions

Request a Correction Request a Correction
View Item View Item

Downloads

Downloads per month over past year