论文标题
激活的涡旋晶格过渡在具有六倍和十二倍各向异性相互作用的超导体中
Activated vortex lattice transition in a superconductor with combined sixfold and twelvefold anisotropic interactions
论文作者
论文摘要
数值模拟用于检查在一个对涡流 - 涡流相互作用的六倍和十二倍贡献的系统中亚稳态和基态涡流晶格阶段之间的过渡动力学。该系统最初使用十二倍各向异性退火，得出两个不同方向的结构域，并通过晶界隔开。然后突然将涡流 - 涡流相互作用更改为六倍各向异性，从而使十二倍状态稳定。应用模拟振荡磁场的驱动器会导致亚稳态状态衰减，这是由从十二到六个峰演变的结构因子所表明的。结果符合MGB2中涡旋晶格的最新小角度中子散射研究所见的行为。在较高的驱动幅度下，衰减表现出一个两步的过程，其中最初的快速减小之后是一个较慢的机制，在该方案中，雪崩或爆发与脱位灭绝事件相关。将结果与其他类型的亚稳态系统进行比较，这些系统具有周期性外部驱动器下腐烂的猝灭障碍。
Numerical simulations are used to examine the transition dynamics between metastable and ground state vortex lattice phases in a system with combined sixfold and twelvefold contributions to the vortex-vortex interactions. The system is initially annealed using a twelvefold anisotropy, yielding domains of two different orientations and separated by grain boundaries. The vortex-vortex interaction is then suddenly changed to a sixfold anisotropy, rendering the twelvefold state metastable. Applying a drive that mimics an oscillating magnetic field causes the metastable state to decay, indicated by the structure factor that evolves from twelve to six peaks. The results fit the behavior seen in recent small-angle neutron scattering studies of the vortex lattice in MgB2. At higher drive amplitudes, the decay exhibits a two step process in which the initial fast decrease is followed by a slower regime where avalanches or bursts are correlated with dislocation annihilation events. The results are compared to other types of metastable systems with quenched disorder that decay under a periodic external drive.
