The terahertz response in 10-100 cm-1 was investigated in an organic dimer-Mott (DM) insulator κ-(ET)2Cu2(CN) 3 that exhibits a relaxorlike dielectric anomaly. An ∼30 cm -1 band in the optical conductivity was attributable to collective excitation of the fluctuating intradimer electric dipoles that are formed by an electron correlation. We succeeded in observing photoinduced enhancement of this ∼30 cm-1 band, reflecting the growth of the electric dipole cluster in the DM phase. Such optical responses in κ-(ET) 2Cu2(CN)3 reflect an instability near the boundary between the DM-ferroelectric charge ordered phases.
ASJC Scopus subject areas
- General Physics and Astronomy