Berlin 2024 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 23: Ultrafast Electron Dynamics at Surfaces and Interfaces III
O 23.9: Vortrag
Dienstag, 19. März 2024, 12:30–12:45, MA 041
Doping-Induced Modulation of Charge Density Wave States in 1T-TaS2: Ultrafast Insights — •Jesumony Jayabalan1, Florian K. Diekmann2, Negar Najafianpour1, Ping Zhou1, Walter Schnelle3, Martin Eckstein4, Kai Rossnagel2, and Uwe Bovensiepen1 — 1Universität Duisburg-Essen, Germany — 2Christian-Albrechts-Universität zu Kiel, Germany — 3Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany — 4University of Hamburg-CFEL, 22761 Hamburg, Germany
1T-TaS2 displays diverse charge density wave (CDW) ordered states influenced by temperature-dependent electron-electron and electron-phonon coupling. Chemically doping 1T-TaS2 provides a potential means to adjust these couplings, thus modifying the material’s properties. This presentation reports the ultrafast response of doped 1T-TaS2 mainly in incommensurate CDW state, aiming to understand changes in electronic and structural properties. We present results on periodic lattice distortions induced by an infra-red ultrafast pulse, measured using ultraviolet time-resolved photoemission spectroscopy. Samples were doped with W or Mo by substituting a fraction of Ta during growth. Alongside temperature-dependent static photoemission, resistivity, and low energy electron diffraction studies, we demonstrate that the amplitude of oscillation and damping time are strongly influenced by CDW formation, dependent on the level of doping. We find that the defect atoms act as scattering centers which hinders the oscillations causing an increased damping with doping. Funding by the DFG through FOR 5249 QUAST is gratefully acknowledged.
Keywords: Charge density waves; Strongly correlated systems; Electron-Phonon interactions; Quantum Materials