Abstract
The family of materials represents quasi-one-dimensional quarter filled systems exhibiting insulator-to-metal (I-M) phase transition at thermal equilibrium. is known to undergo a photoinduced I-M conversion with cooperative response to light excitation. Here we use femtosecond pump-probe experiments to study the photoresponse of made of a larger counteranion compared to the well studied . In the early stage of the photoinduced process, we reveal a multicomponent coherent oscillating feature. The evolution of this feature with excitation density and temperature points to the local nature of the photoswitching in . At longer time scale, we did not detect the features associated with the transformation to the M phase, albeit observed in the derivative. We propose a scenario whereby the bigger size of the counteranion in hinders the establishment of this transformation at macroscopic scale.
3 More- Received 15 October 2014
DOI:https://doi.org/10.1103/PhysRevB.92.024304
©2015 American Physical Society