Emergence of Non-Fermi Liquid Behavior with Quantum Criticality in Transition Metal Dichalcogenides.

Ali, Nasir; Wang, Zhenping; Shin, Hoseong; Park, Hyokwang; Waheed, Sobia; Ali, Fida; Lee, Sungwon; Choi, Hyungyu et al. · ACS Nano · 2026

basic_science · Level V

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Abstract

Unraveling the microscopic origins of non-Fermi liquid behavior near a quantum critical point (QCP) remains a central puzzle in condensed matter physics. A key challenge lies in disentangling the often-coexisting roles of Coulomb interactions and disorder. Here, we use transition metal dichalcogenides (TMDs)─PdSe<sub>2</sub>, WSe<sub>2</sub>, and MoS<sub>2</sub>─as prototypes to understand how Coulomb interactions and disorder govern the electrical resistivity of metals near the QCP. We show that resistivity exhibits Fermi liquid behavior at low temperatures and <i>T</i>-linear resistivity at intermediate temperatures in the deep metallic phase of these systems. As the metal-insulator boundary approaches, the low-temperature Fermi liquid phase turns into the <i>T</i>-linear resistivity in PdSe<sub>2</sub> and transitions to an electron glass in WSe<sub>2</sub> and MoS<sub>2</sub> by increasing the strength of Coulomb interactions and degree of disorder. Further, resistivity develops distinct nonmonotonic <i>T</i>-dependencies in these systems while approaching the metal-insulator boundary, suggesting different microscopic origins of resistivity. This dichotomy is corroborated by quantum critical scaling, which reveals divergent universality classes. This study establishes TMDs as a promising platform for understanding the interplay between Coulomb interactions and disorder in the quantum critical regime.