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

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 first ultrafast investigation of TaTe2, which exhibits unique charge and lattice trimer order characterised by a transition upon cooling from stripe-like chains into a $(3\times 3)$ superstructure of trimer clusters. Utilising MeV-scale ultrafast electron diffraction, we capture the photo-induced TaTe2 structural dynamics -- exposing a rapid $\approx 1.4$ 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.

arXiv commentMain text and supplementary information: 30 pages, 4 main figures, 24 supplementary figures

References in corpus (19)

• Topological Insulators
• 2D materials and van der Waals heterostructures
• Weyl and Dirac Semimetals in Three Dimensional Solids
• Ultrafast switching to a stable hidden topologically protected quantum state in an electronic crystal
• Electronic structure of quantum materials studied by angle-resolved photoemission spectroscopy
• Nanoscale manipulation of the Mott insulating state coupled to charge order in 1T-TaS2
• Non-thermal separation of electronic and structural orders in a persisting charge density wave
• Disentangling amplitude and phase dynamics of a charge density wave in a photo-induced phase transition
• Phase-ordering of charge density waves traced by ultrafast low-energy electron diffraction
• How optical excitation controls the structure and properties of vanadium dioxide
• Polytypism, polymorphism and superconductivity in TaSe2-xTex
• Phase Fluctuations and the Absence of Topological Defects in Photo-excited Charge Ordered Nickelate
• Ultrafast dynamics of charge density waves in 4Hb-TaSe2 probed by femtosecond electron diffraction
• Ultrafast transmission electron microscopy on dynamic process of a CDW transition in 1T-TaSe2
• Ultrafast Relativistic Electron Nanoprobes
• Anisotropic magneto-transport and magnetic properties of low temperature phase of TaTe2
• Trimer Bonding States on the Surface of Transition-metal Dichalcogenide TaTe2
• Ultrafast Dynamics of Vibrational Symmetry Breaking in a Charge-ordered Nickelate
• Ultrafast decoupling of atomic sublattices in a charge-density-wave material

Cited by in corpus (1)

• INQ, a modern GPU-accelerated computational framework for (time-dependent) density functional theory