Ultrafast optical melting of trimer superstructure in layered 1T'-TaTe2

2020/09/30 by Khalid M. Siddiqui, Daniel B. Durham, Frederick Cropp +15
Chemistry · Materials Science · Physics and Astronomy · #2D Materials and Applications #Atomic physics #Charge density wave #Chemical physics #Chemistry #Cluster (spacecraft) #Computational chemistry #Condensed matter physics #Density functional theory #Diffraction #Electron diffraction #Excitation #Graphene research and applications #Laser #Machine Learning in Materials Science #Materials science #Molecular dynamics #Molecular physics #Nanoscopic scale #Nanotechnology #Optics #Physics #Quantum Dots Synthesis And Properties #Superconductivity #Superstructure #Thermalisation #Thermodynamics #Transition metal #Trimer #Ultrafast electron diffraction #Ultrashort pulse #cond-mat.mes-hall #cond-mat.mtrl-sci #cond-mat.str-el

paper · pdf · doi:10.1038/s42005-021-00650-z

published as Communications Physics, Volume 4, Article number 152 (2021) · Main text and supplementary information: 30 pages, 4 main figures, 24 supplementary figures

arxiv created 2021/11/09 · arxiv updated 2021/11/11 · openalex publication_date 2023/07/04 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05

Abstract

Quasi-two-dimensional transition-metal dichalcogenides are a key platform for exploring emergent nanoscale phenomena arising from complex interactions. Access to the underlying degrees-of-freedom on their natural time scales motivates the use of advanced ultrafast probes sensitive to self-organised atomic-scale patterns. Here, we report the ultrafast investigation of TaTe₂, which exhibits unique charge and lattice trimer order characterised by a transition upon cooling from stripe-like chains into a (3 × 3) superstructure of trimer clusters. Utilising MeV-scale ultrafast electron diffraction, we capture the photo-induced TaTe₂ structural dynamics – exposing a rapid ≈ 1.4 ps melting of its low-temperature ordered state followed by recovery via thermalisation into a hot cluster superstructure. Density-functional calculations indicate that the initial quench is triggered by intra-trimer Ta charge transfer which destabilises the clusters, unlike melting of charge density waves in other TaX₂ compounds. Our work paves the way for further exploration and ultimately rapid optical and electronic manipulation of trimer superstructures.

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