Reentrant dynamics of driven pancake vortices in layered superconductors

Article

关键词: FLUX-LINE-LATTICE;    MOVING GLASS PHASE;    VORTEX LATTICES;    II SUPERCONDUCTORS;    MIXED-STATE;    DISORDER;    SYSTEMS;   

DOI  :  10.1103/PhysRevB.94.024514

来源: SCIE

【 摘 要 】

The dynamics of driven pancake vortices in layered superconductors is studied using molecular-dynamics simulations. We found that, with increasing driving force, for strong interlayer coupling, the preexisted vortex lines either directly depin or first transform to two-dimensional (2D) pinned states before they are depinned, depending on the pinning strength. In a narrow region of pinning strengths, we found an interesting repinning process, which results in a negative differential resistance. For weak interlayer coupling, individually pinned pancake vortices first form disordered 2D flow and then transform to ordered three-dimensional (3D) flow with increasing driving force. However, for extremely strong pinning, the random pinning-induced thermal-like Langevin forces melt 3D vortex lines, which results in a persistent 2D flow in the fast-sliding regime. In the intermediate regime, the peak effect is found: With increasing driving force, the moving pancake vortices first crystallize to moving 3D vortex lines, and then these 3D vortex lines are melted, leading to the appearance of a reentrant 2D flow state. Our results are summarized in a dynamical phase diagram.

【 授权许可】

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