2025/10/30 by Yichi Zhang, Wenjin Zhao, Zhang, Yichi +11
Materials Science · Physics and Astronomy · #FOS: Physical sciences #Mesoscale and Nanoscale Physics (cond-mat.mes-hall) #Organic and Molecular Conductors Research #Rare-earth and actinide compounds #Strongly Correlated Electrons (cond-mat.str-el) #Topological Materials and Phenomena
paper · doi:10.48550/arxiv.2510.26958
openalex publication_date 2025/10/30 · openalex created_date 2025/11/05 · openalex updated_date 2026/07/28
Tunable Kondo lattice and heavy fermion physics have been recently reported in moiré materials, but most of the studies have focused on the electrical and magnetic properties. Quantitative thermoelectric measurements, which can reveal entropic information of the heavy fermions, have yet to be achieved. Here, we report a comprehensive thermoelectric study on the moiré heavy fermion phase realized in hole-doped angle-aligned MoTe2/WSe2 bilayers. By electrically gating the material to the Kondo lattice region of the phase diagram, we observe a sign change in the Seebeck coefficient near the Kondo coherence temperature, where the heavy fermion phase with an electronlike Fermi surface evolves into an itinerant Fermi liquid with a holelike Fermi surface. We compare the results with the semiclassical Mott relation and discuss the observed discrepancies. In addition to the thermal dissociation of Kondo singlets in the heavy Fermi liquid, a sign change accompanied by a strong peak in the Seebeck coefficient is also observed near a Zeeman breakdown of the Kondo singlets, signaling an entropy accumulation. Our results provide entropic information on both the formation and breakdown of heavy fermions in moiré semiconductors.