Ultrafast photoinduced conductivity reduction by bonding orbital control in an incommensurate crystal

In this paper, we demonstrate the ultrafast reduction of conductivity in an incommensurate crystal structure within hundreds of femtoseconds. This phenomenon stands in stark contrast to most prior experimental investigations where incident light pulses led to increased conductivity. We achieve this by selectively targeting a specific atomic bond using near-infrared light pulses. Our investigation focuses on misfit layered chalcogenide (LaS)1.196VS2, known as LaVS3, a semimetal with incommensurability along one crystallographic direction. Our time-resolved electron dynamics investigation reveals that the conductivity decreases as photoexcited electrons are promoted into localized energy states within vanadium clusters due to the incommensurate structure. These findings offer insights into the potential for controlling electronic properties at femtosecond time scales, with implications for the development of ultrafast electronic devices