Dynamics of resistive state in thin superconducting channels

Article

关键词: CURRENT-CARRYING STATES;    PHASE-SLIP CENTERS;    LINES;    FILAMENTS;    FIELD;   

DOI  :  10.1103/PhysRevB.87.174516

来源: SCIE

【 摘 要 】

We study theoretically how the dynamics of the resistive state in narrow superconducting channels shunted by an external resistor depends on channel's length L, the applied current j, and parameter u characterizing the penetration depth of the electric field in nonequilibrium superconductors. We show that changing u dramatically affects both the behavior of the current-voltage characteristics of the superconducting channels and the dynamics of their order parameter. Previously, it was demonstrated that when u is less than the critical value u(c1), which does not depend on L, the phase slip centers appear simultaneously at different spots of the channel. Herewith, for u > u(c1) these centers arise consecutively at the same place. In our work we demonstrate that there is another critical value for u. Actually, if u does not exceed a certain value u(c2), which depends on L, the current-voltage characteristic exhibits the step-like behavior. However, for u > u(c2) it becomes hysteretic. In this case, with increase of j the steady state, which corresponds to the time-independent distribution of the order parameter along the channel, losses its stability at switching current value j(sw), and time-periodic oscillations of both the order parameter and electric field occur in the channel. As j sweeps down, the periodic dynamics ceases at certain retrapping current value j(r) < j(sw). Shunting the channel by a resistor increases the value of j(r), while j(sw) remains unchanged. Thus, for some high-enough conductivity of the shunt, jr and jsw eventually coincide, and the hysteretic loop disappears.

【 授权许可】

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