Electrodynamics of quantum spin liquids

Abstract

Quantum spin liquids attract great interest due to their exceptional magnetic properties characterized by the absence of long-range order down to low temperatures despite the strong magnetic interaction. Commonly, these compounds are strongly correlated electron systems, and their electrodynamic response is governed by the Mott gap in the excitation spectrum. Here we summarize and discuss the optical properties of several two-dimensional quantum spin liquid candidates. First we consider the inorganic material Herbertsmithite ZnCu${}_3$(OH)${}_6$Cl${}_2$ and related compounds, which crystallize in a kagome lattice. Then we turn to the organic compounds ${\beta }^{\prime }$-EtMe${}_3$\-Sb\-[Pd(dmit)${}_2$]${}_2$, $\kappa$-(BEDT-TTF)${}_2$Ag${}_2$(CN)${}_3$ and $\kappa$-(BEDT-TTF)${}_2$Cu${}_2$(CN)${}_3$, where the spins are arranged in an almost perfect triangular lattice, leading to strong frustration. Due to differences in bandwidth, the effective correlation strength varies over a wide range, leading to a rather distinct behavior as far as the electrodynamic properties are concerned. We discuss the spinon contributions to the optical conductivity in comparison to metallic quantum fluctuations in the vicinity of the Mott transition.

20 pages, 13 figures

References in corpus (32)

• Quantum Spin Liquid States
• Spin Dynamics of the Spin-1/2 Kagome Lattice Antiferromagnet ZnCu_3(OH)_6Cl_2
• Projected wavefunction study of Spin-1/2 Heisenberg model on the Kagome lattice
• Herbertsmithite and the Search for the Quantum Spin Liquid
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• Critical fermi surfaces and non-fermi liquid metals
• The magnetic groundstate of an experimental $S=1/2$ kagomé antiferromagnet
• Numerical-Diagonalization Study of Spin Gap Issue of the Kagome Lattice Heisenberg Antiferromagnet
• Disorder-Induced Entanglement in Spin Ice Pyrochlores
• Bandwidth-controlled Mott transition in $\kappa -(BEDT-TTF{)}_{2}Cu[N(CN{)}_2]B{r}_{x}C{l}_{1-x}$ I. Optical studies of localized charge excitations
• Absence of charge order in the dimerized κ-phase BEDT-TTF salts
• Pressure-Tuned Exchange Coupling of a Quantum Spin Liquid in the Molecular Triangular Lattice $\kappa$-(ET)${}_2$Ag${}_2$(CN)${}_3$
• Bandwidth-controlled Mott transition in kappa-(BEDT-TTF)2Cu[N(CN)2]Br{x}Cl{1-x}: Optical studies of correlated carriers
• Dynamics and transport of the Z_2 spin liquid: application to kappa-(ET)2Cu2(CN)3
• Quasiparticles at the verge of localization near the Mott metal-insulator transition in a two-dimensional material
• Anisotropic charge dynamics in the quantum spin-liquid candidate $\kappa$-(BEDT-TTF)${}_2$Cu${}_2$(CN)${}_3$
• Ab initio two-dimensional multiband low-energy models of EtMe_3Sb[Pd(dmit)_2]_2 and κ-(BEDT-TTF)_2Cu(NCS)_2 with comparisons to single-band models
• Power-law Conductivity inside the Mott gap: application to $\kappa -(BEDT-TTF{)}_{2}C{u}_2(CN{)}_3$
• Power-law dependence of the optical conductivity observed in the quantum spin-liquid compound κ-(BEDT-TTF)2Cu2(CN)3
• Anions effects on the electronic structure and electrodynamic properties of the Mott insulator $\kappa$-(BEDT-TTF)${}_2$Ag${}_2$(CN)${}_3$
• Nature of optical excitations in the frustrated kagome compound Herbertsmithite
• Emergent U(1) gauge theory with fractionalized boson/fermion from the bose condensation of exciton in multi-band insulator
• Low-Energy Excitations in Quantum Spin-Liquids Identified by Optical Spectroscopy
• Infrared phonons as a probe of a spin-liquid states in herbertsmithite ZnCu3(OH)6Cl2
• Importance of van der Waals interactions and cation-anion coupling in an organic quantum spin liquid
• The magneto-optical Faraday effect in spin liquid candidates
• Fate of spinons at the Mott point

Cited by in corpus (10)

• 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
• Impurity Moments Conceal Low-Energy Relaxation of Quantum Spin Liquids
• Lattice dynamics in the spin-1/2 frustrated kagome compound herbertsmithite
• Phase coexistence at the first-order Mott-transition revealed by pressure-dependent dielectric spectroscopy of $\kappa$-(BEDT-TTF)${}_2$Cu${}_2$(CN)${}_3$
• Low-Energy Excitations in Quantum Spin-Liquids Identified by Optical Spectroscopy
• Coherent heavy charge carriers in an organic conductor near the bandwidth-controlled Mott transition
• Universal dielectric response across a continuous metal-insulator transition
• Transition of a prestine Mott insulator to a correlated Fermi liquid: Pressure-dependent optical investigations of a quantum spin liquid
• Charge localization in strongly correlated $\kappa$-(BEDT-TTF)${}_2$Cu[N(CN)${}_2$]I due to inherent disorder