"Direct Measurement of Current-Phase Relations in Superconductor/Topological Insulator/Superconductor Junctions"

Ilya Sochnikov: Andrew J. Bestwick, James R. Williams, Thomas M. Lippman, Ian R. Fisher, David Goldhaber-Gordon, John R. Kirtley, and Kathryn A. Moler; Nano Letters, 06/24/13.

Additional Authors: Andrew J. Bestwick, James R. Williams, Thomas M. Lippman, Ian R. Fisher, David Goldhaber-Gordon, John R. Kirtley, and Kathryn A. Moler

Abstract:

Proximity to a superconductor is predicted to induce exotic quantum phases in topological insulators. Here, scanning superconducting quantum interference device (SQUID) microscopy reveals that aluminum superconducting rings with topologically insulating Bi2Se3 junctions exhibit a conventional, nearly sinusoidal 2π-periodic current-phase relations. Pearl vortices occur in longer junctions, indicating suppressed superconductivity in aluminum, probably due to a proximity effect. Our observations establish scanning SQUID as a general tool for characterizing proximity effects and for measuring current-phase relations in new materials systems.