Ultrafast photo-response in (EDO)₂PF₆

Abstract

Organic conductor (EDO) 2 PF 6 crystal shows a noble metal (M) insulator (I) transition accompanied with charge ordering, anion ordering and changes in the magnetic character and molecular conformation at T c = 280 K. This M-I transition can be also sensitively probed by spectroscopic method. Here, we report the reflectivity change in (EDO) 2 PF 6 crystal induced by the irradiation of weak femto-second (fs) pulsed laser (pulse width: 120 fs) which has been observed utilizing the pump-probe technique. The photo-induced spectral changes strongly suggest the occurrence of the very fast and highly efficient photo-conversion from insulator to metal in the temperature region between 180 K and 270K. Under certain condition, a half (50%) of the crystal surface was converted into another phase by one excitation photon for every 1000 EDO molecules.