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

• DOI: 10.1038/s41467-017-02679-7
• Publication Date: 2018-01-16T10:05:09Z
• Authors: Tetsuya Furukawa; Kazuhiko Kobashi; Yosuke Kurosaki; Kazuya Miyagawa; Kazushi Kanoda
• Keywords: Spinon; Mott transition; Mott insulator; Metal–insulator transition; Strongly correlated material

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 insulator carries spin liquid with spinon Fermi surface. Here, we demonstrate case quasi-continuous from to in an organic triangular-lattice system κ-(ET)2Cu2(CN)3. Transport experiments performed under fine pressure tuning have found approached, coherence temperature continuously falls scale kelvins, divergent quasi-particle decay rate on metal side, and charge gap closes side. A Clausius-Clapeyron analysis provides thermodynamic evidence for extremely weak first-order nature These results provide additional support existence surface, which becomes electron surface when charges are delocalized.