Anomalous Josephson effect in planar noncentrosymmetric superconducting devices

TL;DR

This paper investigates the anomalous Josephson effect in planar noncentrosymmetric superconducting devices, revealing a nonzero supercurrent at zero phase difference due to broken symmetries, using theoretical models.

Contribution

It provides a detailed analysis of the anomalous Josephson effect in planar hybrid circuits with Rashba spin-orbit coupling, combining Ginzburg-Landau and Green's functions approaches.

Findings

Critical current magnitude depends on in-plane magnetic field orientation.

Anomalous phase shifts are derived in various limiting cases.

Theoretical framework explains supercurrent behavior at zero phase difference.

Abstract

In two-dimensional electron systems with broken inversion and time-reversal symmetries, a Josephson junction reveals an anomalous response: the supercurrent is nonzero even at zero phase difference between two superconductors. We consider details of this peculiar phenomenon in the planar double-barrier configurations of hybrid circuits, where the noncentrosymmetric normal region is described in terms of the paradigmatic Rashba model of spin-orbit coupling. We analyze this anomalous Josephson effect by means of both the Ginzburg-Landau formalism and the microscopic Green's functions approach in the clean limit. The magnitude of the critical current is calculated for an arbitrary in-plane magnetic field orientation, and anomalous phase shifts in the Josephson current-phase relation are determined in terms of the parameters of the model in several limiting cases.