Observation of anomalous Josephson effect in nonequilibrium Andreev interferometers

Abstract

The evidence of anomalous Josephson effect in superconducting-normal-superconducting (SNS) junctions requiring neither Zeeman splitting nor spin-orbit coupling is reported. We demonstrate that a spontaneous phase emerges by modifying the nonequilibrium conditions of the weak link resembling ${\ensuremath{\varphi}}_{0}$-junctions. The voltage-controlled phase shift is detected from magnetoresistance measurements of the proximitized wire connected to the weak link forming a crosslike Andreev interferometer. The interplay of Aharanov-Bohm-like and conventional Josephson currents, in agreement with recent predictions, provides the ingredients for the anomalous current-phase relation. These results represent a breakthrough for engineering superconducting nanocircuits with voltage-tunable quantum properties.