Quasi-continuous transition from a Fermi liquid to a spin liquid in κ-(ET)2Cu2(CN)3

Tetsuya Furukawa, Kazuhiko Kobashi, Yosuke Kurosaki, Kazuya Miyagawa, Kazushi Kanoda

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32 Citations (Scopus)


The Mott metal-insulator transition-A manifestation of Coulomb interactions among electrons-is known as a discontinuous transition. Recent theoretical studies, however, suggest that the transition is continuous if the Mott insulator carries a spin liquid with a spinon Fermi surface. Here, we demonstrate the case of a quasi-continuous Mott transition from a Fermi liquid to a spin liquid in an organic triangular-lattice system κ-(ET)2Cu2(CN)3. Transport experiments performed under fine pressure tuning have found that as the Mott transition is approached, the Fermi liquid coherence temperature continuously falls to the scale of kelvins, with a divergent quasi-particle decay rate on the metal side, and the charge gap continuously closes on the insulator side. A Clausius-Clapeyron analysis provides thermodynamic evidence for the extremely weak first-order nature of the transition. These results provide additional support for the existence of a spinon Fermi surface, which becomes an electron Fermi surface when charges are delocalized.

Original languageEnglish
Article number307
JournalNature Communications
Issue number1
Publication statusPublished - 2018 Dec 1


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