Optical Properties of the Two Crystal Modifications of the Organic Conductor (BEDT-TTF)2I3

Abstract

Polarised reflectivity spectra in the region 200 to 30000 cm−1 are investigated for the two crystal modifications of (BEDT-TTF)2I3: the dielectric α-phase and the superconducting β-phase. For both phases the electronic reflection bands with a Drude-like edge are observed in two perpendicular polarisations at room temperature, for the α-phase the most intense electronic band being observed in the direction perpendicular to BEDT-TTF stacks. In the IR spectra of both phases the bands due to the interaction of molecular vibrations with conduction electrons are observed. For the α-phase the IR reflection spectra at temperatures above and below the dielectric transition points are obtained and an increasing number of bands in the vibrational region is found below the transition point. [Russian Text Ignored].