Berlin 2024 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 44: 2D Materials III: Electronic Structure (joint session O/TT)
O 44.4: Vortrag
Mittwoch, 20. März 2024, 11:15–11:30, MA 005
On the the nature of transient and metastable nonequilibrium phases in 1T-TaS2 — •Tanusree Saha1,2, Arindam Pramanik3, Barbara Ressel1, Alessandra Ciavardini1, Primož Rebernik Ribič4, and Giovanni De Ninno1,4 — 1University of Nova Gorica, 5270 Ajdovščina, Slovenia — 2Universität Duisburg-Essen, 47057 Duisburg, Germany — 3Tata Institute of Fundamental Research, Mumbai 400005, India — 4Elettra Sincrotrone Trieste, 34149 Trieste, Italy
Photoexcitation of materials with complex ground states can drive them into new out-of-equilibrium phases. In this talk, I will present the characteristics of these phases and the recovery dynamics in a complex system, the charge density wave (CDW)-Mott insulator 1T-TaS2, studied using time- and angle-resolved photoemission spectroscopy. We observe strong similarities between the band structures of the transient phase and the structurally undistorted equilibrium phase, with evidence for the coexistence of insulating and metallic phases. Following the transient phase, we find that the restorations of Mott and CDW orders begin around the same time, highlighting that the Mott transition is tied to the CDW distortion. During recovery, a metastable phase, driven by the CDW lattice order, emerges but only in the strong photoexcitation regime and is a commensurate CDW-Mott insulating phase but with a smaller CDW amplitude. Finally, I will briefly discuss our future work, where we aim to study how the nature of the metastable phase and electron correlations in photoexcited 1T-TaS2 can be tuned by an external parameter, e.g. pump fluence.
Keywords: Electron correlations; Transient and metastable phases; Charge density wave; Timescales; Time-resolved photoemission