Dresden 2017 – wissenschaftliches Programm
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MA: Fachverband Magnetismus
MA 31: Ultrafast Electron and Spin Dynamics
MA 31.5: Poster
Dienstag, 21. März 2017, 18:30–20:30, P2-EG
Ultrafast transition to a hidden state in 1T-TaS2−xSex single crystals — •Ljupka Stojchevska1,2, Ebru Ekici3, Kira Kolpatzeck3, Christian A. Bobisch3, Dragan Mihailovic1, and Uwe Bovensiepen2 — 1Complex Matter Department, Jozef Stefan Institute, Ljubljana, Slovenia — 2Faculty of Physics, University of Duisburg-Essen, Duisburg, Germany — 3Faculty of Physics, Center for Nanointegration Duisburg-Essen (CENIDE), University of Duisburg-Essen, Duisburg, German
We report on femtosecond pump-probe spectroscopy study on the relaxation dynamics in 1T-TaS2−xSex single crystals with 6%, 7.5%, 17% and 19% selenium doping. We observe a transition to a new hidden state [1] (H-state) which is inaccessible under normal equilibrium conditions and can only be reached after a quench with a single femtosecond laser pulse at 1.6-4.8 mJ/cm2 fluence. Similarly as in [1], a notable change in the coherent phonon spectra plays the role of the fingerprint of the successful switching to a new state via optical path. The major output is observation of the significantly higher temperature stability of the H-state (∼ 104 K) in comparison with the parent 1T-TaS2 material (∼ 70 K). In addition, intense experimental efforts are currently undergoing in order to microscopically characterize H-state by means of scanning tunneling microscopy (STM) and to investigate the electronic structure with femtosecond time- and angle-resolved photoemission spectroscopy (trARPES). [1] Stojchevska, L. et al., Science, 344, 177 (2014).