We study the effect of a magnetic field on the current-phase relation of a topological Josephson junction formed by connecting two superconductors through the helical edge states of a quantum spin-Hall insulator. We predict that the Zeeman effect along the spin quantization axis of the helical edges results in an anomalous Josephson relation that allows for a supercurrent to flow in the absence of superconducting phase bias. We relate the associated field-tunable phase shift phi0 in the Josephson relation of such a phi0-junction to the existence of a so-called helical superconductivity, which may result from the interplay of the Zeeman effect and spin-orbit coupling. We analyze the dependence of the magneto-supercurrent on the junction length and discuss its observability in suitably designed hybrid structures subject to an in-plane magnetic field.
|Titolo:||Topological Josephson phi0-junctions|
|Data di pubblicazione:||2015|
|Digital Object Identifier (DOI):||10.1103/PhysRevB.92.035428|
|Appare nelle tipologie:||1.1 Articolo in rivista|