Dresden 2020 – wissenschaftliches Programm
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TT 66.16: Poster
Donnerstag, 19. März 2020, 15:00–19:00, P2/EG
Thermal and nonthermal responses of the low temperature charge order in IrTe2 to femtosecond laser pulses — •Gregor Jecl1, Venera Nesretdinova2, Yaroslav Gerasimenko1, Claude Monney3, Fabian von Rohr4, and Dragan Mihailovic1,2 — 1Department for Complex Matter, Jozef Stefan Institute, Slovenia — 2Center of Excellence on Nanoscience and Nanotechnology, Slovenia — 3Département de Physique and Fribourg Center for Nanomaterials, Université de Fribourg, Switzerland — 4Department of Chemistry, University of Zürich, Switzerland
IrTe2 is a layered material which exhibits a structural transition at TC1 = 275 K to a low temperature (LT1) phase which is accompanied by the appearance of stripe order. A second transition (LT2 phase) at TC2 = 180 K changes the dominant periodicity of the stripes. Superconductivity can be introduced below 3.1 K by doping or in undoped samples at surface patch domains of hexagonal symmetry. We have investigated the dynamics of all three phases on sub-picosecond timescales by means of ultrafast optical spectroscopy in a temperature range between 8 and 295 K. Additionally, by imaging the surface after photoexcitation in STM, we have investigated the degree to which the stripe order can be controlled by ultrafast optical pules on long timescales. At helium temperatures and under high fluence photoexcitation we observe a non-thermal photoinduced response of the transient reflectivity. Additionally, exposure to high fluence pulse trains results in the stabilisation of the LT1 phase at low temperatures and to changes in the orientation of the stripe phase.