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HL: Fachverband Halbleiterphysik

HL 36: Poster III

HL 36.32: Poster

Mittwoch, 20. März 2024, 18:00–20:30, Poster E

Light induced dynamics in a coupled van der Waals heterostructure — •Mashood Tariq Mir, Arne Ungeheuer, Ahmed Hassanien, Lukas Nöding, Arne Senftleben, and Thomas Baumert — University of Kassel, Institute of Physics and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), D-34132 Kassel, Germany

Layered transition metal dichalcogenides (TMDs) host a rich collection of physical properties, opening many applications with atomically thin films such as sensors, electronic switching, or energy storage. Among those materials, 1T-TaS2 exhibits a complex phase diagram depending on temperature encompassing charge density waves (CDW) with diverse commensurabilities. New phenomena have been observed and are further expected from combining different materials to 2D heterojunctions. We employ the UED technique to investigate the light-induced dynamics in the sub-ps time regime. This work uses femtosecond laser pulses to induce rapid structural changes in a free-standing van der Waals heterostructure. Upon lattice heating, the CDW material undergoes several phase transitions. We focus on the reversible phase transition 1T-TaS2 from the nearly commensurate to the incommensurate phase. In addition, we present an initial UED study on the optically excited CAPs in a stacked (1T-TaS2 / Graphite) heterostructure.

Keywords: van der Waals heterostructure; Charge density wave; Phase transitions; Coherent acoustic phonons; ultrafast electron diffraction