Measurement of the Nonlinear Conducting States of α-(BEDT-TTF)2I3 Using Electronic Raman Scattering

Nonlinear conducting states in a strongly correlated organic electronic system alpha-(BEDT-TTF)(2)I-3 [BEDT-TTF = bis(ethylenedithio)-tetrathiafulvalene] are studied by Raman spectroscopy. Wide-range Raman spectra of nonlinear conducing states provide direct information about conducting properties through the electronic Raman process. A comparison between the behaviors of the electronic modes of BEDT-TTF layers and the vibrational mode of I-3 molecules reveals the formation of nonequilibrium states in which only the electronic parts show the change of states. We obtained a spatial map of the conducting regions of the nonlinear conducting states by utilizing the electronic Raman intensity as a measure of the highly conducting states. A spatially inhomogeneous formation of nonlinear conducting states was observed.