Absence of charge order in the dimerized κ-phase BEDT-TTF salts

Abstract

Utilizing infrared vibrational spectroscopy we have investigated dimerized two-dimensional organic salts in order to search for possible charge redistribution that might cause electronic dipoles and ferroelectricity: the quantum spin liquid κ-(BEDT-TTF)2Cu2(CN)3, the antiferromagnetic Mott insulator κ-(BEDT-TTF)2$Cu[N(CN)2]Cl,andthesuperconductor\kappa -(BEDT-TTF)2$Cu[N(CN)2]Br. None of them exhibit any indication of charge disproportionation upon cooling down to low temperatures. No modification in the charge distribution is observed around T = 6 K where a low-temperature anomaly has been reported for the spin-liquid κ-(BEDT-TTF)2$Cu2(CN)3. In this compound the in-plane optical response and vibrational coupling are rather anisotropic, indicating that the tilt of the BEDT-TTF molecules in c-direction and their coupling to the anion layers has to be considered in the explanation of the electromagnetic properties.

11 pages, 9 figures, 1 table

References in corpus (11)

• Mott Transition from a Spin Liquid to a Fermi Liquid in the Spin-Frustrated Organic Conductor kappa-(ET)2Cu2(CN)3
• Quantum frustration in organic Mott insulators: from spin liquids to unconventional superconductors
• Theoretical Aspects of Charge Ordering in Molecular Conductors
• Emergence of inhomogeneous moments from spin liquid in the triangular-lattice Mott insulator $\kappa$-(ET)${}_2$Cu${}_2$(CN)${}_3$
• 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
• Bandwidth-controlled Mott transition in kappa-(BEDT-TTF)2Cu[N(CN)2]Br{x}Cl{1-x}: Optical studies of correlated carriers
• Ordering phenomena in quasi one-dimensional organic conductors
• Quasiparticles at the verge of localization near the Mott metal-insulator transition in a two-dimensional material
• Power-law dependence of the optical conductivity observed in the quantum spin-liquid compound κ-(BEDT-TTF)2Cu2(CN)3
• Spin diffusion and magnetic eigenoscillations confined to single molecular layers in the organic conductors kappa-(BEDT-TTF)_2Cu[N(CN)_2X (X=Cl, Br)
• Charge Order Breaks Magnetic Symmetry in Molecular Quantum Spin Chains

Cited by in corpus (3)

• Anisotropic charge dynamics in the quantum spin-liquid candidate $\kappa$-(BEDT-TTF)${}_2$Cu${}_2$(CN)${}_3$
• Ferroelectric properties of charge-ordered alpha-(BEDT-TTF)2I3
• ESR studies on the spin-liquid candidate $\kappa$-(BEDT-TTF)${}_2$Cu${}_2$(CN)${}_3$: anomalous response below $T=8$ K