Field-induced carrier delocalization in the strain-induced Mott insulating state of an organic superconductor

Abstract

We report the influence of the field effect on the dc resistance and Hall coefficient in the strain-induced Mott insulating state of an organic superconductor $\kappa$-(BEDT-TTF)${}_2$Cu[N(CN)${}_2$]Br. Conductivity obeys the formula for activated transport ${\sigma }_{\square }={\sigma }_0\exp (-W/k_{B}T)$, where ${\sigma }_0$ is a constant and $W$ depends on the gate voltage. The gate voltage dependence of the Hall coefficient shows that, unlike in conventional FETs, the effective mobility of dense hole carriers ($\sim 1.6\times 10^{14}$ cm${}^{-2}$) is enhanced by a positive gate voltage. This implies that carrier doping involves delocalization of intrinsic carriers that were initially localized due to electron correlation.

5 pages, 3 figures

References in corpus (2)

• Imaging phase separation near the Mott boundary in the correlated organic superconductors $\kappa$-(BEDT-TTF)${}_2$X
• Precise Determination of Phase Diagram for Two-Dimensional Hubbard Model with Filling- and Bandwidth-Control Mott Transitions: Grand-Canonical Path-Integral Renormalization Group Approach