Abstract

We consider the motion of superconducting vortices and skyrmions on a square substrate near the first commensurate matching field. Slightly above commensuration, a series of dynamic phases appears including interstitial flow, and there is a transition from fluid flow to soliton flow that generates negative differential conductivity. Slightly below commensuration, vacancy depinning occurs. The dynamic phase transitions produce features in the velocity–force curves, differential mobility, and velocity fluctuations. In this work we have gone to much longer simulation times than in previous work, allowing us to examine the differential conductivity curves over a larger range of vortex and pinning densities. When a Magnus force is also present, as in certain superconducting vortex or skyrmion systems, there is an expansion of the fluid state, and at lower drives there is a finite Hall angle in the fluid phase but a vanishing Hall angle in the soliton phase, giving rise to a reentrant Hall effect. We also find a regime where the Hall motion of the particles exhibits the same dynamic phases, including soliton motion at a finite angle that produces negative differential conductivity in the Hall response but not in the longitudinal response. Our results suggest that vortices driven over periodic pinning may be an ideal system for determining if a vortex Hall effect is occurring and would also be relevant for skyrmions at smaller Magnus forces.

Graphic abstract

中文翻译：

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周期性钉扎阵列上涡旋和斯格明子的动态相位和重入霍尔效应

摘要

我们考虑在第一个相称匹配场附近的方形基板上超导涡旋和斯格明子的运动。略高于相应，出现了一系列动态相，包括间隙流动，并且存在从流体流动到产生负微分电导率的孤子流动的转变。略低于相称，出现空位脱钉。动态相变产生速度-力曲线、微分迁移率和速度波动的特征。在这项工作中，我们的模拟时间比以前的工作要长得多，这使我们能够检查更大范围内的涡旋和钉扎密度的微分电导率曲线。当马格努斯力也存在时，例如在某些超导涡旋或斯格明子系统中，流体状态会膨胀，在较低的驱动下，流体相中的霍尔角有限，而孤子相中的霍尔角消失，从而产生重入霍尔效应。我们还发现了一种状态，其中粒子的霍尔运动表现出相同的动态相位，包括有限角度的孤子运动，在霍尔响应中产生负微分电导率，但在纵向响应中没有。我们的结果表明，通过周期性钉扎驱动的涡流可能是确定涡旋霍尔效应是否发生的理想系统，并且也与较小马格努斯力下的斯格明子相关。包括有限角度的孤子运动，在霍尔响应中产生负微分电导率，但在纵向响应中没有。我们的结果表明，通过周期性钉扎驱动的涡流可能是确定涡旋霍尔效应是否发生的理想系统，并且也与较小马格努斯力下的斯格明子相关。包括有限角度的孤子运动，在霍尔响应中产生负微分电导率，但在纵向响应中没有。我们的结果表明，通过周期性钉扎驱动的涡流可能是确定涡旋霍尔效应是否发生的理想系统，并且也与较小马格努斯力下的斯格明子相关。

图形摘要