Optical Study of Two-Dimensional Organic Metal (EO-TTP) 2AsF 6 (EO-TTP=2-(4,5-Ethylenedioxy-1,3-Dithiol-2-Ylidene)-5-(1,3-Dithiol-2-Ylidene)-1,3,4,6-Tetrathiapentalene)

Abstract

Polarized reflectance spectra were measured on the conductive (010) plane of metallic (EO-TTP) 2AsF 6 single crystal. At room temperature, well-defined plasma edges appeared in both directions parallel ( E|| a) and perpendicular ( E⊥ a) to the molecular stack. The intra- and inter-stack transfer integrals were estimated from the plasma frequencies in the framework of tight-binding model. Based on these transfer integrals, we suggested that the Fermi surface was open in the k c direction. Using a generalized Drude model, we obtained the frequency dependence of relaxation rate, which conformed to γ(ω)=γ 0+bω 2 in the frequency range 1800–5500 cm −1.