$^{27}$Al NMR study of the magnetic Weyl semimetal CeAlGe

Abstract: Motivated by the recent observations of electronic correlation effect [M. Corasaniti \textit{et al}., Phys. Rev. B \textbf{104}, L121112 (2021)] and topology-stabilized magnetic fluctuations [N. Drucker \textit{et al}., Nat. Commun. \textbf{14}, 5182 (2023)] in the noncentrosymmetric magnetic Weyl semimetal candidate CeAlGe, we performed systematic studies on the local static and dynamic spin susceptibilities by $^{27}$Al nuclear magnetic resonance. Due to the large spin susceptibility from Ce-$4f$ electrons, the theoretically predicted responses from Weyl fermions are overwhelmed. A Knight-shift anomaly is observed below $T^*\sim50$ K, a signature of the onset of coherent Kondo coupling. In addition, an anomalous peak is found in $1/T_1T$ near 15 K, well above the magnetic ordering temperature $T_N \approx 5$ K, which probably is a consequence of topology-stabilized magnetic fluctuations. These results highlight the interplay among electronic correlation, magnetism and band topology in this family of Kondo Weyl semimetals.