Regensburg 2025 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 29: Poster II

HL 29.94: Poster

Dienstag, 18. März 2025, 18:00–20:00, P1

Ultrafast dynamics reveal proximity induced changes in Graphite — •Mashood Tariq Mir, Ahmed Hassanien, Arne Ungeheuer, Lukas Nöding, Arne Senftleben, and Thomas Baumert — University of Kassel, Institute of Physics, D-34132 Kassel, Germany

Layered transition metal dichalcogenides (TMDs) are at the forefront of materials research due to their diverse electronic and structural properties. Among these materials, 1T-TaS2 exhibits a complex temperature-dependent phase diagram characterized by charge density waves (CDWs) of varying commensurabilities. When integrated into heterostructures, novel interfacial phenomena emerge, enabling the study of proximity effects in atomically thin materials. This work investigates the light-induced dynamics of a van der Waals heterostructure composed of 1T-TaS2 and graphene using ultrafast electron diffraction (UED). Femtosecond laser pulses induce rapid structural changes, revealing a proximity-induced CDW in graphene. This observation demonstrates how interfacial coupling can imprint the characteristic periodic lattice modulation of CDWs onto an otherwise non-CDW material. By controlling lattice heating, we probe the reversible phase transition of 1T-TaS2 from the nearly commensurate to the incommensurate phase and its influence on the interfacial properties of the heterostructure.

Keywords: Proximity effect; Ultrafast electron diffraction; van der Waals Heterostructures; Phase transition; Charge density waves