2016 Volume 71 Issue 5 Pages 311-317
Ultrafast photoinduced transitions of a one-dimensional Mott insulator to two distinct electronic phases, metal and charge-density-wave (CDW) phases, were successfully achieved in a bromine-bridged Pd-chain compound. By the high-energy excitation in the Mott insulator phase, free electron and hole carriers are produced, giving rise to an insulator to metal transition. By the resonant excitation of the Mott-gap transition, excitonic states are initially generated in the Mott insulator phase, and subsequently converted to one-dimensional CDW domains. Photoinduced Mott insulator to CDW transition is quite intriguing because it is the transition from a higher-symmetry phase to a lower-symmetry phase. Such selectivity in photoconversions by the choice of the initial photoexcited states opens a new possibility for the developments of advanced optical switching and memory functions.
