Percolative transport in the metal-insulator phase coexistence region of Mott organics*

The Mott metal-insulator transition of the organic triangular-lattice system k−(ET)₂Cu₂(CN)₃ has recently been re-examined through low temperature DC [1] transport experiments. These results, displaying striking non-monotonous temperature dependence for a family of resistivity curves, have been previously interpreted in terms of the “continuous" (spinon-based) scenario for the transition. Here we theoretically re-examine the transport properties in this regime, and show that an alternative viewpoint [2], based in the dynamical mean-field theory (DMFT) and a percolation picture [3], naturally explains all the observed anomalies. According to this scenario, the transition assumes first-order character at low temperature, leading to percolative transport in the coexistence regime, which we study theoretically, reproducing the experimental trends.
[1] Tetsuya Furukawa et al., Nature Comm. 9, 307 (2018).
[2] H. Terletska et al., Phys. Rev. Lett. 107, 026401 (2011).
[3] H. Terletska and V. Dobrosavljevic, Phys. Rev. Lett. 106, 186402 (2011).