Incommensurate magnetic order drives singular angular magnetoresistance in a Weyl semimetal
X. Yao, P. Chen, R. Verma, X. Zhao, H. -Y. Yang, L. DeBeer-Schmitt, A. A. Aczel, C. -M. Wu, D. Alba Venero, T. Ohhara, K. Munakata, M. Takahashi, Y. Noda, A. Bansil, B. Singh, P. Nikolić, F. Tafti, J. Gaudet
公開日: 2025/9/22
Abstract
We demonstrate that a multi-$\mathbf{k}$ incommensurate magnetic state in the Weyl semimetal CeAlGe gives rise to singular angular magnetoresistance (SAMR), an electrical-transport signature that detects the magnetic-field direction with exceptional precision. In contrast, the sister compound CeAlSi shows neither multi-$\mathbf{k}$ order nor SAMR. Both phenomena emerge upon $\sim57\%$ Ge substitution in CeAlSi$_{1-x}$Ge$_x$ and coincide with electronic-structure changes that soften the single-ion in-plane anisotropy and enhance Weyl-mediated magnetic interactions. These results reveal a direct connection between band topology, electronic transport, and collective magnetism in Weyl semimetals.