Infrared Properties of the Magnetic Semiconductor DBTTF-TCNQC12

Abstract
Dibenzo-TTF-dichloro-TCNQ constitutes a particularly clean example of a strongly Coulomb correlated, incommensurate organic conductor. The bands are narrow, and are near quarter-filled. The infrared chain axis excitation spectrum is that of a semiconductor with a sizeable energy gap of 1500-2000 cm”1. In addition the spectrum has strong absorption bands near molecular vibration frequencies. The strength of these indicates that they arise from the electron-molecular vibration coupling. They are apparently activated by 4kF-charge density waves. The overall behavior is consistent with a model, where strong Coulomb correlations exclude double occupancy of sites.