Nonequilibrium ac Josephson Effect in Mesoscopic Nb-InAs-Nb Junctions
Nonequilibrium ac Josephson Effect in Mesoscopic Nb-InAs-Nb Junctions
Microwave irradiation of Nb-InAs-Nb junctions reveals frequency-doubled Josephson currents which persist to high temperatures, in the absence of a critical current. A nonequilibrium dynamical model, based on time-dependent Andreev bound states, successfully accounts for the resulting half-integer Shapiro step and an enhancement in the conductance near zero bias.