Gapped magnetic ground state in the spin-liquid candidate $\kappa$-(BEDT-TTF)${}_2$Ag${}_2$(CN)${}_3$ suggested by magnetic spectroscopy

Abstract

The nature of the magnetic ground state of highly frustrated systems remained puzzling to this day. Here, we have performed multifrequency electron spin resonance (ESR) measurements on a putative quantum spin liquid compound $\kappa$-(BEDT-TTF)${}_2$Ag${}_2$(CN)${}_3$, which is a rare example of $S=1/2$ spins on a triangular lattice. At high temperatures, the spin susceptibility exhibits a weak temperature dependence which can be described by the Heisenberg model with an antiferromagnetic exchange interaction of strength $J/k_B\approx 175$ K. At low temperatures, however, the rapid drop of the static spin susceptibility, together with monotonic decrease of the ESR linewidth indicates that strong singlet correlations develop below a pairing energy scale $T^{\ast }$ accompanied by a spin gap. On the other hand, a weak Curie-like spin susceptibility and the angular dependence of the linewidth suggest additional contribution from impurity spins. We propose the gradual formation of spin singlets with an inhomogeneous spin gap at low temperatures.

References in corpus (46)

• Quantum Spin Liquid States
• Spin Liquid State in an Organic Mott Insulator with Triangular Lattice
• Quantum Spin Liquids
• Experimental Realization of Spin-1/2 Triangular-Lattice Heisenberg Antiferromagnet
• Spin liquid nature in the Heisenberg $J_1$-$J_2$ triangular antiferromagnet
• Spin liquid phase of the $S=\frac{1}{2}$ $J_1-J_2$ Heisenberg model on the triangular lattice
• Magnetization Process and Collective Excitations in the S=1/2 Triangular-Lattice Heisenberg Antiferromagnet Ba3CoSb2O9
• Competing Spin Liquid States in the Spin-$1/2$ Heisenberg Model On Triangular Lattice
• Valence Bonds in Random Quantum Magnets: Theory and Application to YbMgGaO4
• Chiral spin liquid phase of the triangular lattice Hubbard model: a density matrix renormalization group study
• Revision of model parameters for kappa-type charge transfer salts: an ab initio study
• Gapless ground state in the archetypal quantum kagome antiferromagnet ZnCu${}_3$(OH)${}_6$Cl${}_2$
• Dirac Spin Liquid on the Spin-1/2 Triangular Heisenberg Antiferromagnet
• Lattice effects and entropy release at the low-temperature phase transition in the spin-liquid candidate $\kappa$-(BEDT-TTF)${}_2$Cu${}_2$(CN)${}_3$
• Witnessing quantum criticality and entanglement in the triangular antiferromagnet KYbSe${}_2$
• Pressure-Tuned Exchange Coupling of a Quantum Spin Liquid in the Molecular Triangular Lattice $\kappa$-(ET)${}_2$Ag${}_2$(CN)${}_3$
• Ground state phase diagram of the triangular lattice Hubbard model by density matrix renormalization group method
• Gapped magnetic ground state in quantum-spin-liquid candidate $\kappa$-(BEDT-TTF)${}_2$-Cu${}_2$(CN)${}_3$
• Quantum Spin Liquids Unveil the Genuine Mott State
• Importance of Spin-Orbit Coupling in Organic BEDT-TTF and BEDT-TSF Salts
• Nature of the randomness-induced quantum spin liquids in two dimensions
• Random-Singlet Phase in Disordered Two-Dimensional Quantum Magnets
• Critical Spin Liquid versus Valence Bond Glass in Triangular Lattice Organic $\kappa$-(ET)${}_2$Cu${}_2$(CN)${}_3$
• Symmetry Reduction in the Quantum Kagome Antiferromagnet Herbertsmithite
• Phase diagram of the anisotropic triangular lattice Hubbard model
• Molecular Quantum Materials: Electronic Phases and Charge Dynamics in Two-Dimensional Organic Solids
• Structural and magnetic dimers in the spin-gapped system CuTe2O5
• Magnetic anisotropy reversal driven by structural symmetry-breaking in monolayer α-RuCl3
• Quantum Spin Liquid with Emergent Chiral Order in the Triangular-lattice Hubbard Model
• Emergence of spin singlets with inhomogeneous gaps in the kagome Heisenberg antiferromagnets Zn-barlowite and herbertsmithite
• Power-law dependence of the optical conductivity observed in the quantum spin-liquid compound κ-(BEDT-TTF)2Cu2(CN)3
• Microwave spectroscopy on heavy-fermion systems: probing the dynamics of charges and magnetic moments
• Anions effects on the electronic structure and electrodynamic properties of the Mott insulator $\kappa$-(BEDT-TTF)${}_2$Ag${}_2$(CN)${}_3$
• Spectral function of the $J_1-J_2$ Heisenberg model on the triangular lattice
• Impurity Moments Conceal Low-Energy Relaxation of Quantum Spin Liquids
• Curie-law crossover in spin liquids
• Spin correlations and Dzyaloshinskii-Moriya interaction in Cs${}_2$CuCl${}_4$
• Nature of quantum spin liquids of the S=1/2 Heisenberg antiferromagnet on the triangular lattice: A parallel DMRG study
• Superconducting coplanar microwave resonators with operating frequencies up to 50 GHz
• Ingredients for Generalized Models of $\kappa$-Phase Organic Charge-Transfer Salts: A Review
• ESR studies on the spin-liquid candidate $\kappa$-(BEDT-TTF)${}_2$Cu${}_2$(CN)${}_3$: anomalous response below $T=8$ K
• Cryogenic frequency-domain electron spin resonance spectrometer based on coplanar waveguides and field modulation
• Chasing the spin gap through the phase diagram of a frustrated Mott insulator
• Novel Dipole-Lattice coupling in the Quantum-Spin-Liquid Material $\kappa$-(BEDT-TTF)${}_2$Cu${}_2$(CN)${}_3$
• Possible glass-like random singlet magnetic state in 1T-TaS2
• Understanding the magnetic response of the Quantum spin liquid compound 1T-TaS2