Charge localization in strongly correlated $\kappa$-(BEDT-TTF)${}_2$Cu[N(CN)${}_2$]I due to inherent disorder

Abstract

In order to understand the physical properties of the series of organic conductors $\kappa$-(BEDT-TTF)${}_2$Cu[N(CN)${}_2$]$X$ with $X$ = Cl, Br, and I, not only electronic correlations but also the effect of disorder has to be taken into account. While for Cl- and Br-containing salts the influence of both parameters were investigated and a universal phase diagram was proposed, the position of $\kappa$-(BEDT-TTF)${}_2$Cu[N(CN)${}_2$]I is still not settled. Here we have conducted transport, infrared, and dielectric measurements on single crystals of the title compound to clarify its electronic state at low temperatures. The correlation strength was determined as $U/W\approx 2.2$; thus this salt is placed deeper in an insulating state compare to the two sister compounds. We found that inherent disorder leads to a Coulomb localized insulating state similar to the moderately x-ray-irradiated $\kappa$-(BEDT-TTF)${}_2$Cu[N(CN)${}_2$]Cl.

References in corpus (9)

• 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
• Bandwidth-controlled Mott transition in kappa-(BEDT-TTF)2Cu[N(CN)2]Br{x}Cl{1-x}: Optical studies of correlated carriers
• Molecular Quantum Materials: Electronic Phases and Charge Dynamics in Two-Dimensional Organic Solids
• Power-law dependence of the optical conductivity observed in the quantum spin-liquid compound κ-(BEDT-TTF)2Cu2(CN)3
• Electronic Griffiths phase of the d=2 Mott transition
• Electron localization near Mott transition in organic superconductor $\kappa$-(BEDT-TTF)${}_2$Cu[N(CN)${}_2]$Br
• Optical probe of carrier doping by X-ray irradiation in organic dimer Mott insulator $\kappa$-(BEDT-TTF)${}_2$Cu[N(CN)${}_2]$Cl
• Interacting electron spins in $\kappa$-(BEDT-TTF)${}_2$Cu[N(CN)${}_2$]I investigated by ESR spectroscopy

Cited by in corpus (1)

• Charge-localization-driven metal-insulator phase transition in layered molecular conductors