title: Josephson Currents Induced by the Witten Effect.
abstract: 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 the 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.
authors: Institute for Theoretical Solid State Physics, IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany.|Institut für Theoretische Physik III, Ruhr-Universität Bochum, Universitätsstraße 150, 44801 Bochum, Germany.
authors: Flavio S
authors: FS
authors: Nogueira
authors: Physics Department, CB 1105, Washington University, 1 Brookings Drive, St. Louis, Missouri 63130-4899, USA.
authors: Zohar
authors: Z
authors: Nussinov
authors: Institute for Theoretical Solid State Physics, IFW Dresden, Helmholtzstrasse 20, 01069 Dresden, Germany.|Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA.
authors: Jeroen
authors: J
authors: van den Brink