Farajollahpour T, Ganesh R, Samokhin K V
Department of Physics, Brock University, Ontario, Canada.
NPJ Quantum Mater. 2025;10(1):77. doi: 10.1038/s41535-025-00805-z. Epub 2025 Jul 17.
Altermagnetism has been detected in several materials using spin-sensitive probes. These measurements require rather complex setups that make it challenging to track variations in altermagnetic order, e.g., to identify a temperature-tuned altermagnetic phase transition. We propose a simple transport measurement that can probe the order parameter for -wave altermagnetism. We suggest magnetoconductivity anisotropy-the difference between the two principal values of the magnetoconductivity tensor. This quantity can be easily measured as a function of temperature, without any spin-selective apparatus. It acquires a nonzero value in a phase, where rotations and time reversal are not symmetries but their combination is. This effect can be traced to the modification of phase space density due to Berry curvature, which we demonstrate using semiclassical equations of motion for band electrons. As an illustration, we build a minimal tight-binding model with altermagnetic order that breaks and symmetries while preserving .
利用自旋敏感探针已在几种材料中检测到交变磁性。这些测量需要相当复杂的装置，这使得追踪交变磁序的变化具有挑战性，例如识别温度调谐的交变磁相变。我们提出一种简单的输运测量方法，它可以探测d波交变磁性的序参量。我们建议采用磁导率各向异性——磁导率张量两个主值之间的差值。这个量可以很容易地作为温度的函数进行测量，而无需任何自旋选择装置。它在一个特定相中获得非零值，在该相中，自旋旋转和时间反演不是对称操作，但它们的组合是对称操作。这种效应可以追溯到由于贝里曲率导致的相空间密度的修改，我们使用能带电子的半经典运动方程对此进行了证明。作为一个例证，我们构建了一个具有交变磁序的最小紧束缚模型，该模型破坏了自旋旋转和时间反演对称性，同时保留了其他对称性。
