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arXiv · 2305.01033

Transition between heavy-fermion strange metal and quantum spin liquid in a 4d-electron trimer lattice

Hengdi Zhao·Yu Zhang·Pedro Schlottmann·Rahul Nandkishore·Gang Cao
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Abstract

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.

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Hengdi Zhao, Yu Zhang, Pedro Schlottmann, Rahul Nandkishore, Gang Cao. 2023-05-01. Transition between heavy-fermion strange metal and quantum spin liquid in a 4d-electron trimer lattice. https://doi.org/10.1103/physrevlett.132.226503

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