Electronic Raman scattering spectra of various types of BEDT-TTF compounds

We measured Raman scattering spectra of various types of BEDT-TTF compounds such as a charge ordered material α-(BEDT-TTF)₂I₃, a dimer-square lattice material β-(BEDT-TTF)₂I₃ and a quantum spin-liquid material κ-(BEDT-TTF)₂Ag₂(CN)₃. These three compounds show the broad Raman structures, which can be ascribed to the electronic Raman scattering. These structures correspond to charge excitation and magnetic excitation. Comparing these electronic Raman signals, we will discuss the electronic states of these compounds. For example, α-(BEDT-TTF)₂I₃ shows a phase transition from charge ordered state to Dirac electron state. For clarification of the electronic state of α-(BEDT-TTF)₂I₃, we focus on the charge excitation in the reflectivity and Raman spectra.