Transport properties of an organic Mott insulator '-(BEDT-TTF)2ICl2N. Tajima1, R. Kato1 and H. Taniguchi2
1 RIKEN - Hirosawa 2-1, Wako-shi, Saitama 351-0198, Japan
2 Saitama University - Shimo-Ohkubo 225, Saitama, 338-8570, Japan
received 12 February 2008; accepted in final form 4 June 2008; published July 2008
published online 5 July 2008
We have investigated the temperature dependence of the Hall coefficient and the resistivity of an organic Mott insulator, -(BEDT-TTF)2ICl2 under ambient and hydrostatic pressures up to 2 GPa. The charge gap, , the effective mass, m*, and the scattering lifetime of carriers on Mott Hubbard bands were evaluated by analyzing these transport properties. We found that m* and are written approximately as in the low-pressure region and obtained the value of the effective on-site Coulomb energy, Ueff, of ~ 445meV. Moreover, we reveal that the effective scattering lifetime is proportional to the average distance between carriers in the two-dimensional plane, which suggests the existence of a scattering process attributable to carrier-carrier umklapp scattering in the Mott insulating state.
75.47.-m - Magnetotransport phenomena; materials for magnetotransport.
72.15.Gd - Galvanomagnetic and other magnetotransport effects.
71.20.Rv - Polymers and organic compounds.
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