Observation of Anomalous Josephson Effect in Nonequilibrium Andreev Interferometers

Abstract

The first evidence of anomalous Josephson effect is reported in mesoscopic superconductor-normal metal-superconductor (SNS) junctions forming a crosslike Andreev Interferometer in the absence of magnetic and spin-orbit interactions normally required to break time-reversal and inversion symmetries. From conductance measurements of the out-of-equilibrium weak link, we determine a voltage-controlled spontaneous phase that resembles a $\varphi_0$-junction. The temperature and voltage dependences together with a dissipative term in the current-phase relation strongly suggest that the mechanism underlying the observed phenomenon relies on electron-hole asymmetries.