Carrier duality from the convergence of Dirac fermions and high-order van Hove singularities
Year: 2026
Type: preprint
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.
Source: arXiv (Cornell University)
Institutions: State Key Laboratory of Low-Dimensional Quantum Physics, Tsinghua University, Max Planck Institute for Chemical Physics of Solids, Chinese Academy of Sciences, Diamond Light Source, University of Oxford, Institute of Physics, ShanghaiTech University, Frontier Science Center for Quantum Information of the Ministry of Education of China, High Magnetic Field Laboratory
Language: English
Subfield: Condensed Matter Physics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7214007604