Berlin 2012 – wissenschaftliches Programm

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O: Fachverband Oberflächenphysik

O 8: Electron and spin dynamics

O 8.2: Vortrag

Montag, 26. März 2012, 10:45–11:00, A 060

The role of the excitation pathway in the photoinduced melting of the CDW in 1T-TiSe₂ — •Gerald Rohde, Stefan Hellmann, Timm Rohwer, Christian Sohrt, Ankatrin Stange, Kerstin Hanff, Lutz Kipp, Michael Bauer, and Kai Rossnagel — Institut für Experimentelle und Angewandte Physik der Christian-Albrechts-Universität zu Kiel

Charge-density waves (CDWs) are broken-symmetry states of low-dimensional solids that are brought about by strong electron-phonon or electron-electron interaction. In a time-resolved XUV ARPES study we recently showed that the long-range order associated with the CDW phase in the transition metal dichalcogenide 1T-TiSe₂ can be destroyed within less than 30 fs after intense illumination with a 800 nm light pulse [1]. In this contribution we present complementary data recorded at pulsed 400 nm excitation. Surprisingly we find that for the short-wavelength excitation the CDW collapse is considerably slowed down. Our time-resolved ARPES data show furthermore that the initiating absorption processes take place at well separated locations in electron momentum space for the two different wavelengths. Possible scenarios that consider the effect of the absorption pathway on the phase transition dynamics will be discussed.
T. Rohwer et al., Nature 471, 490 (2011)