Dresden 2017 – scientific programme
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TT: Fachverband Tiefe Temperaturen
TT 14: Superconductivity: Tunnelling, Josephson Junctions, SQUIDs 1
TT 14.11: Talk
Monday, March 20, 2017, 18:00–18:15, HSZ 201
Josephson currents induced by the Witten effect — •Flavio Nogueira1, Jeroen van den Brink2, and Zohar Nussinov3 — 1Institut für Theoretische Physik III, Ruhr-Universität Bochum — 2Institute for Theoretical Solid State Physics, IFW Dresden — 3Physics Department, CB 1105, Washington University
We reveal the existence of a new type of topological Josephson effect involving type II superconductors and three-dimensional topological insulators as tunnel junctions. We predict that vortex lines induce a variant of the Witten effect that is the consequence of the axion electromagnetic response of the topological insulator: at the interface of the junction each flux quantum attains a fractional electrical charge of e/4. As a consequence, if an external magnetic field is applied perpendicular to the junction, the Witten effect induces an AC Josephson effect in absence of any external voltage. We derive a number of further experimental consequences and propose potential setups where these quantized, flux induced, Witten effects may be observed.
[1] F. S. Nogueira, Z. Nussinov, and J. van den Brink, Phys. Rev. Lett. 117, 167002 (2016)
[2] F. S. Nogueira, Z. Nussinov, and J. van den Brink, Phys. Rev. D 94, 085003 (2016)