Quasi-continuous transition from a Fermi liquid to a spin liquid

Abstract

The Mott metal-insulator transition-a drastic manifestations of Coulomb interactions among electrons-is the first-order transition of clear discontinuity, as shown by various experiments and the celebrated dynamical mean-field theory. Recent theoretical works, however, suggest that the transition is continuous if the Mott insulator carries an exotic 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 k-(ET)2Cu2(CN)3. Transport experiments performed under fine pressure tuning find that, as the Mott transition is approached, the Fermi-liquid coherence temperature continuously falls to the scale of kelvins with divergent quasi-particle decay rate in the metal side and the charge gap gradually closes in the insulator side. The Clausius-Clapeyron analysis of the pressure-temperature phase diagram provides thermodynamic evidence for the extremely weak first-order nature of the Mott transition. These results suggest that the spin liquid hosts a spinon Fermi surface, which turns into an electron Fermi surface when charges are Mott delocalized.

References in corpus (21)

• Quantum Spin Liquid States
• Spin Liquid State in an Organic Mott Insulator with Triangular Lattice
• Variational study of triangular lattice spin-1/2 model with ring exchanges and spin liquid state in κ-(ET)_2 Cu_2 (CN)_3
• Continuous excitations of the triangular-lattice quantum spin liquid YbMgGaO4
• U(1) Gauge Theory of the Hubbard Model : Spin Liquid States and Possible Application to k-(BEDT-TTF)_2 Cu_2 (CN)_3
• Mott transition, antiferromagnetism, and unconventional superconductivity in layered organic superconductors
• Evidence for a spinon Fermi surface in a triangular lattice quantum spin liquid candidate
• Mott Transition from a Spin Liquid to a Fermi Liquid in the Spin-Frustrated Organic Conductor kappa-(ET)2Cu2(CN)3
• Unconventional critical behaviour in a quasi-two-dimensional organic conductor
• Theory of a continuous Mott transition in two dimensions
• Emergence of inhomogeneous moments from spin liquid in the triangular-lattice Mott insulator $\kappa$-(ET)${}_2$Cu${}_2$(CN)${}_3$
• Lattice effects and entropy release at the low-temperature phase transition in the spin-liquid candidate $\kappa$-(BEDT-TTF)${}_2$Cu${}_2$(CN)${}_3$
• Phase diagram of the Hubbard model on the anisotropic triangular lattice
• Novel Pauli-paramagnetic quantum phase in a Mott insulator
• Anisotropic charge dynamics in the quantum spin-liquid candidate $\kappa$-(BEDT-TTF)${}_2$Cu${}_2$(CN)${}_3$
• Universal transport near a quantum critical Mott transition in two dimensions
• A continuous Mott transition between a metal and a quantum spin liquid
• Field-induced staggered magnetic moment in the quasi-two-dimensional organic Mott insulator $\kappa$-(BEDT-TTF)${}_2$Cu[N(CN)${}_2$]Cl
• Precise Determination of Phase Diagram for Two-Dimensional Hubbard Model with Filling- and Bandwidth-Control Mott Transitions: Grand-Canonical Path-Integral Renormalization Group Approach
• Spin Liquid States at the vicinity of metal-insulator transition
• Fate of spinons at the Mott point

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• Metal-insulator transition in transition metal dichalcogenide heterobilayer moiré superlattices
• Molecular Quantum Materials: Electronic Phases and Charge Dynamics in Two-Dimensional Organic Solids
• Rise and Fall of Landau's Quasiparticles While Approaching the Mott Transition
• Entanglement entropy and mutual information across the Mott transition in the two-dimensional Hubbard model
• Spectral function of the $J_1-J_2$ Heisenberg model on the triangular lattice
• Low-Temperature Dielectric Anomalies at the Mott Insulator-Metal Transition
• Mott-driven BEC-BCS crossover in a doped spin liquid candidate, kappa-(BEDT-TTF)4Hg2.89Br8
• Extraordinary $\pi$-Electron Superconductivity Emerging from a Quantum Spin Liquid
• Disorder-induced spin-liquid-like behavior in kagome-lattice compounds
• Disorder-induced broadening of the spin waves in a triangular-lattice quantum-spin-liquid candidate YbZnGaO${}_4$
• Mechanism of the insulator-to-metal transition and superconductivity in the spin liquid candidate NaYbSe${}_2$ under pressure
• Phase coexistence at the first-order Mott-transition revealed by pressure-dependent dielectric spectroscopy of $\kappa$-(BEDT-TTF)${}_2$Cu${}_2$(CN)${}_3$
• Recent progress on magnetic-field studies on quantum-spin-liquid candidates
• Charge disproportionation in the spin-liquid candidate $\kappa$-(ET)${}_2$Cu${}_2$(CN)${}_3$ at 6 K revealed by ${}^{63}$Cu NQR measurements
• Superconducting-like response in driven systems near the Mott transition
• Thermodynamic determination of the equilibrium first-order phase-transition line hidden by hysteresis in a phase diagram
• Thermoelectric signature of quantum critical phase in a doped spin liquid candidate
• Chasing the spin gap through the phase diagram of a frustrated Mott insulator
• Thermodynamic Properties of the Mott Insulator-Metal Transition in a Triangular Lattice System Without Magnetic Order
• Dynamic charge Kondo effect and a slave fermion approach to the Mott transition
• Interplay between multi-spin and chiral spin interactions on triangular lattice
• Bipartite Fluctuations of Critical Fermi Surfaces
• Persistence of fermionic spin excitations through a genuine Mott transition in $\kappa$-type organics
• Insulator-to-metal Mott transition facilitated by lattice deformation in monolayer $\alpha$-RuCl${}_3$ on graphite
• Scaling behavior of Charge order melting in Magnetic field-Pressure-Temperature space of 2.5% Al doped Pr${}_{0.5}$Ca${}_{0.5}$MnO${}_3$
• Charge-Transfer Complex $\kappa$-(BEST)${}_2$Cu${}_2$(CN)${}_3$ Analogous to Organic Spin Liquid Candidate
• Mott domain walls: a (strongly) non-Fermi liquid state of matter
• The Sound of Electrons Shattering: Current Noise Composition Laws for Electron Fractionalization