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arXiv · 2609.24044

Carrier duality from the convergence of Dirac fermions and high-order van Hove singularities

Meng Lyu·Kaiyi Zhai·Nikolai Peshcherenko·Junyan Liu·Jinying Yang·Subir Sen·Binbin Wang·Langsheng Ling·Zhaosheng Wang·Gang Li·Jieyi Liu·Yang Xu·Xiyang Li·Claudia Felser·Yang Zhang·Wujun Shi·Lexian Yang·Enke Liu
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Abstract

The convergence of highly mobile Dirac fermions and flat-band heavy electrons offers a paradigm for emergent quantum phenomena. However, experimental realization of such intriguing state remains elusive. In this study, we report a dual carrier regime in the kagome metal Co3In2S2, wherein the charge transport is governed by high-mobility electrons while the thermodynamic responses exhibit heavy-electron behavior. This exotic duality arises from the coexistence of topological Dirac fermions and flat-band high-order (4th-order) Van Hove singularities (HOVHSs) at the Fermi surface, as revealed by magnetic-torque quantum oscillation and angle-resolved photoemission spectroscopy. The interaction between Dirac and HOVHS-derived carriers can be captured by a minimal two-pocket model, manifesting as sublinear resistivity above ~100 K and field-induced non-Fermi-liquid behavior at low temperatures. Our study establishes Co3In2S2 as a model platform for exploring many-body physics at the intersection of topology and correlation effects, and provides a foundational framework for designing quantum materials hosting diverse emergent states.

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Meng Lyu, Kaiyi Zhai, Nikolai Peshcherenko, Junyan Liu, Jinying Yang, Subir Sen, Binbin Wang, Langsheng Ling, Zhaosheng Wang, Gang Li, Jieyi Liu, Yang Xu, Xiyang Li, Claudia Felser, Yang Zhang, Wujun Shi, Lexian Yang, Enke Liu. 2026-09-21. Carrier duality from the convergence of Dirac fermions and high-order van Hove singularities. https://arxiv.org/abs/2609.24044

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