Transition between Heavy-Fermion-Strange-Metal and Quantum Spin Liquid in a 4d -Electron Trimer Lattice

Hengdi Zhao, Yu Zhang, Pedro Schlottmann, Rahul Nandkishore, Lance E. Delong, Gang Cao

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We present experimental evidence that a heavy Fermi surface consisting of itinerant, charge-neutral spinons underpins both heavy-fermion-strange-metal (without f electrons) and quantum-spin-liquid states in the 4d-electron trimer lattice, Ba4Nb1-xRu3+xO12(|x|<0.20). These two exotic states both exhibit an extraordinarily large entropy, a linear heat capacity extending into the milli-Kelvin regime, a linear thermal conductivity at low temperatures, and separation of charges and spins. Furthermore, the insulating spin liquid is a much better thermal conductor than the heavy-fermion-strange-metal that separately is observed to strongly violate the Wiedemann-Franz law. We propose that at the heart of this 4d system is a universal, heavy spinon Fermi surface that provides a unified framework for explaining the exotic phenomena observed throughout the entire series. The control of such exotic ground states provided by variable Nb concentration offers a new paradigm for studies of correlated quantum matter.

Original languageEnglish
Article number226503
JournalPhysical Review Letters
Issue number22
StatePublished - May 31 2024

Bibliographical note

Publisher Copyright:
© 2024 authors. Published by the American Physical Society.

ASJC Scopus subject areas

  • General Physics and Astronomy


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