Motivated by recent progress on synthesizing two-dimensional magnetic van der Waals systems, we propose a setup for detecting the topological Berezinskii-Kosterlitz-Thouless phase transition in spin-transport experiments on such structures. We demonstrate that the spatial correlations of injected spin currents into a pair of metallic leads can be used to measure the predicted universal jump of $2/\pi$ in the ferromagnet spin stiffness as well as its predicted universal square root dependence on temperature as the transition is approached from below. Our setup provides a simple route to measuring this topological phase transition in two-dimensional magnetic systems, something which up to now has proven elusive. It is hoped that this will encourage experimental efforts to investigate critical phenomena beyond the standard Ginzburg-Landau paradigm in low-dimensional magnetic systems with no local order parameter.

中文翻译：

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二维铁磁体中通用自旋刚度跳跃的指纹

基于合成二维磁性范德华系统的最新进展，我们提出了一种在自旋传输实验中检测这种结构的拓扑Berezinskii-Kosterlitz-Thouless相变的装置。我们证明了注入自旋电流到一对金属引线中的空间相关性可以用来测量预测的$2/\pi$铁磁体的自旋刚度以及其预测的随温度变化的普遍平方根依赖性，是从下面开始的。我们的设置提供了一种简单的方法来测量二维磁系统中的拓扑相变，到目前为止，这种方法已被证明难以捉摸。希望这将鼓励实验工作来研究在没有局部阶数参数的低维磁系统中超出标准的Ginzburg-Landau范式的临界现象。