Nonstationary Josephson effect for superconductors with spin-density waves

The nonstationary Josephson I¹, interference I², and quasiparticle J current amplitudes through symmetrical and nonsymmetrical (ns) tunnel junctions involving partially dielectrized (partially gapped) superconductors with spin-density waves (SDW’s) and described by the dielectric order parameter Σ were calculated. Riedel-type singularities and jumps for all currents are determined by superconducting order parameter Δ, as well as Σ. It was shown that each current for symmetrical junctions, made up of thermodynamicallyidentical SDW superconductors (with |Σ_left|=|Σ_right|), can exhibit three possible current-voltage characteristics (CVC’s) depending on the relationship between the electrodes’ Σ signs in the course of experiment: (i) one symmetrical CVC for genuinely symmetrical configuration (s) when the dielectric order parameters Σ_left and Σ_right have the same sign for both electrodes and (ii) two nonsymmetrical ones for symmetrical junction in the state of broken symmetry (bs) when Σ_left and Σ_right are opposite in sign. The actual setup choice is at random. Thus, the symmetrical junctions can serve as phase-sensitive indicators for the SDW’s. The ns junctions which include SDW and ordinary BCS superconductors are also studied. The current amplitudes I_ns^1,2 and J_ns are asymmetrical functions of the voltage V and depend on the sign of Σ. Our calculations reveal main features appropriate to CVC’s of tunnel junctions involving the heavy-fermion SDW superconductor URu₂Si₂.