Ultra-fast and sensitive photo-induced phase switching in (EDO-TTF)2PF6

Organic conductor (EDO-TTF)2PF6 crystal having image filled band shows a metal (M)–insulator (I) transition accompanied with Peierls transition, charge ordering, and anion ordering at transition temperature, image. This crystal is an important and fascinating candidate for photo-induced M–I transition because the multi-instability will afford sensitivity to the tiny stimulation. We make the report of the reflectivity change in (EDO-TTF)2PF6 crystal induced by the irradiation of femto-second (fs) pulsed laser (pulse width: 120 fs, main wavelength: 800 nm, repetition rate: 1 kHz). The obtained results indicate that the highly efficient I-to-M transition occurs within 3 ps in this material. Based on these results, the strong electron–lattice cooperative interaction is proved to play an essential role in the driving process of this M–I transition. Also, image filled materials, which show M–I transition, accompanied with the charge ordering, can be classified as fascinating candidates not only for superconductivity but also for photo-induced cooperative phenomena and application in phase switching devices.