The organic Mott insulator κ-(BEDT-TTF)2Cu[N(CN) 2]Cl exhibits highly nonlinear current-voltage characteristics in a low current range at temperatures below 10 K. The nonlinear current-voltage characteristics are similar to those observed in the charge-ordered organic crystals θ-(BEDT-TTF)2MZn(SCN)4 (M=Cs and Rb) and are accounted for in the same way in terms of exciton excitations: The electric field assists the thermal unbinding of pairs of a doublon and a holon that attract each other due to the two-dimensional long-range Coulomb interaction. Dielectric properties are understood within the context of the same model in terms of polarization of the bound pairs. κ-(BEDT-TTF)2Cu[N(CN) 2]Cl has a smaller magnetoconductance than θ-(BEDT-TTF) 2MZn(SCN)4 (M=Cs and Rb), which probably reflects different spin states of the excitations for the Mott and charge-ordered states.
|Journal||Physical Review B - Condensed Matter and Materials Physics|
|Publication status||Published - 2011 Jul 11|
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics