Anions effects on the electronic structure and electrodynamic properties of the Mott insulator $\kappa$-(BEDT-TTF)${}_2$Ag${}_2$(CN)${}_3$

Abstract

The Mott insulator $\kappa$-(BEDT-TTF)${}_2$Ag${}_2$(CN)${}_3$ forms a highly-frustrated triangular lattice of $S=1/2$ dimers with a possible quantum-spin-liquid state. Our experimental and numerical studies reveal the emergence of a slight charge imbalance between crystallographically inequivalent sites, relaxor dielectric response and hopping dc transport. In a broader perspective we conclude that the universal properties of strongly-correlated charge-transfer salts with spin liquid state are an anion-supported valence band and cyanide-induced quasi-degenerate electronic configurations in the relaxed state. The generic low-energy excitations are caused by charged domain walls rather than by fluctuating electric dipoles. They give rise to glassy dynamics characteristic of dimerized Mott insulators, including the sibling compound $\kappa$-(BEDT-TTF)${}_2$Cu${}_2$(CN)${}_3$.

arXiv comment5 pages, 6 figures, submitted to Physical Review B Rapid Communications

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Cited by in corpus (20)

• Quantum Spin Liquids Unveil the Genuine Mott State
• Importance of Spin-Orbit Coupling in Organic BEDT-TTF and BEDT-TSF Salts
• Molecular Quantum Materials: Electronic Phases and Charge Dynamics in Two-Dimensional Organic Solids
• From charge- and spin-ordering to superconductivity in the organic charge-transfer solids
• Evidence for electronically-driven ferroelectricity in the family of strongly correlated dimerized BEDT-TTF molecular conductors
• $ab$-$initio$ Approaches for Low-Energy Spin Hamiltonians
• Metal-Insulator Transition in the Dimerized Organic Conductor $\kappa$-(BEDT-TTF)${}_2$Hg(SCN)${}_2$Br
• Semimetallic and charge-ordered $\alpha$-(BEDT-TTF)${}_2$I${}_3$: on the role of disorder in dc transport and dielectric properties
• Electrodynamics of quantum spin liquids
• Phase coexistence at the first-order Mott-transition revealed by pressure-dependent dielectric spectroscopy of $\kappa$-(BEDT-TTF)${}_2$Cu${}_2$(CN)${}_3$
• Ingredients for Generalized Models of $\kappa$-Phase Organic Charge-Transfer Salts: A Review
• Weak ferromagnetism and glassy state in kappa-(BEDT-TTF)2Hg(SCN)2Br
• Low-Energy Excitations in Quantum Spin-Liquids Identified by Optical Spectroscopy
• Importance of van der Waals interactions and cation-anion coupling in an organic quantum spin liquid
• Algebraic Charge Dynamics of Quantum Spin Liquid b'-EtMe3Sb[Pd(dmit)2]2
• Possible observation of the signature of the bad metal phase and its crossover to a Fermi liquid in K(BEDT-TTF)2Cu(NCS)2 bulk and nanoparticles by Raman scattering
• Quasi-particle propagation across semiconductor-Mott insulator interfaces
• Gapped magnetic ground state in the spin-liquid candidate $\kappa$-(BEDT-TTF)${}_2$Ag${}_2$(CN)${}_3$ suggested by magnetic spectroscopy
• Bound States at Semiconductor -- Mott Insulator Interfaces
• Transmission through multiple Mott insulator - semiconductor wells