CoTe<sub>2</sub> : A Quantum Critical Dirac Metal with Strong Spin Fluctuations.

Siegfried, Peter E; Bhandari, Hari; Qi, Jeanie; Ghimire, Rojila; Joshi, Jayadeep; Messegee, Zachary T; Beeson, Willie B; Liu, Kai et al. · Adv Mater · 2023

basic_science · Level V

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Abstract

Quantum critical points separating weak ferromagnetic and paramagnetic phases trigger many novel phenomena. Dynamical spin fluctuations not only suppress the long-range order, but can also lead to unusual transport and even superconductivity. Combining quantum criticality with topological electronic properties presents a rare and unique opportunity. Here, by means of ab initio calculations and magnetic, thermal, and transport measurements, it is shown that the orthorhombic CoTe<sub>2</sub> is close to ferromagnetism, which appears suppressed by spin fluctuations. Calculations and transport measurements reveal nodal Dirac lines, making it a rare combination of proximity to quantum criticality and Dirac topology.