Ultrafast optical melting of trimer superstructure in layered 1T′-TaTe2

Khalid M. Siddiqui, Daniel B. Durham, Frederick Cropp, Colin Ophus, Sangeeta Rajpurohit, Yanglin Zhu, Johan D. Carlström, Camille Stavrakas, Zhiqiang Mao, Archana Raja, Pietro Musumeci, Liang Z. Tan, Andrew M. Minor, Daniele Filippetto, Robert A. Kaindl

Research output: Contribution to journalArticlepeer-review

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.

Original languageEnglish (US)
Article number152
JournalCommunications Physics
Volume4
Issue number1
DOIs
StatePublished - Dec 2021

ASJC Scopus subject areas

  • Physics and Astronomy(all)

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