Anomalous 2D-confined electronic transport in layered organic charge-glass systems
Abstract
To get insight into the nature of the electronic fluid in the frustration-driven charge glasses, we investigate in-plane and out-of-plane charge transport for several quasi-triangular-lattice organic systems, θ-(BEDT-TTF)2X [X=RbZn(SCN)4, CsZn(SCN)4 and I3]. These compounds host a charge order, charge glass and Fermi liquid, depending on the strength of charge frustration. We find that the resistivity exhibits extremely two-dimensional (2D) anisotropy and contrasting temperature dependence between in the in-plane and out-of-plane directions in the charge glass phase, qualitatively distinguished from the charge order and metallic states. The experimental features indicate that the frustration-induced charge glass carries an anomalous 2D-confined electronic fluid with possible charge excitations other than conventional quasiparticles.