Local response to light excitation in the charge-ordered phase of (EDO-TTF)2SbF6

M. Servol (1) , Nicolas Moisan (1) , Eric Collet (1) , Hervé Cailleau (1) , Wawrzyniec Kaszub (1) , Loic Toupet (1) , Davide Boschetto (2) , Tadahiko Ishikawa (3) , Alain Moréac (1) , Shin-Ya Koshihara (3) , Mitsuhiko Maesato (4) , Mikio Uruichi (5) , Xiangfeng Shao (6) , Yoshiaki Nakano (6) , Hideki Yamochi (6) , Gunzi Saito (4, 6) , Maciej Lorenc (1)

1 IPR - Institut de Physique de Rennes
2 LOA - Laboratoire d'optique appliquée
3 Department of Materials Science [Tokyo]
4 Division of Chemistry [Kyoto]
5 Institute for Molecular Science
6 Research Center for Low Temperature and Materials Sciences

The family of materials (EDO-TTF)2XF6 represents quasi-one-dimensional ¼ filled systems exhibiting insulator-to-metal (I-M) phase transition at thermal equilibrium. (EDO-TTF)2PF6 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 (EDO-TTF)2SbF6 made of a larger counter-anion SbF6 compared to the well studied (EDO-TTF)2PF6. In the early stage of the photoinduced process, we reveal a multi-component coherent oscillating feature. The evolution of this feature with excitation density and temperature points to the local nature of the photoswitching in (EDO-TTF)2SbF6. At longer timescale, we did not detect the features associated with the transformation to the M phase, albeit observed in the PF 6 derivative. We propose a scenario whereby the bigger size of the counter-anion in (EDO-TTF)2SbF6 hinders the establishment of this transformation at macroscopic scale.

Domaines: Science des matériaux [cond-mat.mtrl-sci]

M. Servol, Nicolas Moisan, Eric Collet, Hervé Cailleau, Wawrzyniec Kaszub, et al.. Local response to light excitation in the charge-ordered phase of (EDO-TTF)2SbF6. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2015, 92 (2), pp.024304. ⟨10.1103/PhysRevB.92.024304⟩. ⟨hal-01168113v2⟩