Electrical and Optical Properties of <i>α</i>-(BETS)2I3 and <i>α</i>-(BEDT-STF)2I3

Abstract

Abstract The electrical and optical properties were studied concerning α-(BETS)2I3 and α-(BEDT-STF)2I3, which are isostructural to α-(BEDT-TTF)2I3. It has been shown that α-(BETS)2I3 and α-(BEDT-STF)2I3 undergo metal-insulator transitions at around 50 and 80 K, respectively, and that their electrical resistivities exhibit temperature dependences resembling that of α-(BEDT-TTF)2I3 under high pressure. The optical reflectance spectra of these salts show a two-dimensional nature of their electronic structures, and analyses of the spectral data show that the transverse inter-molecular interaction increases in the order α–(BEDT–TTF)2I3 &amp;lt; α–(BEDT–STF)2I3 &amp;lt; α–(BETS)2I3.