Miguel M-Carmen, Zapperi Stefano
Departament de Física Fonamental, Facultat de Física, Universitat de Barcelona, Diagonal 647, E-08028, Barcelona, Spain.
Nat Mater. 2003 Jul;2(7):477-81. doi: 10.1038/nmat909.
A new class of artificial atoms, such as synthetic nanocrystals or vortices in superconductors, naturally self-assemble into ordered arrays. This property makes them applicable to the design of novel solids, and devices whose properties often depend on the response of such assemblies to the action of external forces. Here we study the transport properties of a vortex array in the Corbino disk geometry by numerical simulations. In response to an injected current in the superconductor, the global resistance associated to vortex motion exhibits sharp jumps at two threshold current values. The first corresponds to a tearing transition from rigid rotation to plastic flow, due to the reiterative nucleation around the disk centre of neutral dislocation pairs that unbind and glide across the entire disk. After the second jump, we observe a smoother plastic phase proceeding from the coherent glide of a larger number of dislocations arranged into radial grain boundaries.
一类新型的人造原子，比如合成纳米晶体或超导体中的涡旋，能自然地自组装成有序阵列。这一特性使其适用于新型固体的设计，以及那些特性往往取决于此类组件对外力作用响应的器件。在此，我们通过数值模拟研究了科贝诺盘几何结构中涡旋阵列的输运特性。响应超导体中注入的电流，与涡旋运动相关的全局电阻在两个阈值电流值处呈现出急剧跳跃。第一个阈值对应从刚性旋转到塑性流动的撕裂转变，这是由于中性位错对在圆盘中心周围反复成核，这些位错对解离并在整个圆盘上滑移。在第二次跳跃之后，我们观察到一个更平滑的塑性阶段，它源于排列成径向晶界的大量位错的协同滑移。
