Momentum-resolved EELS study of collective charge excitations in 1$T$-TaS$_2$

[2608.23492] Momentum-resolved EELS study of collective charge excitations in 1$T$-TaS$_2$ Skip to main content Search Submit Donate Log in Condensed Matter > Strongly Correlated Electrons arXiv:2608.23492 (cond-mat) [Submitted on 24 Aug 2026 ( v1 ), last revised 26 Aug 2026 (this version, v2)] Title: Momentum-resolved EELS study of collective charge excitations in 1$T$-TaS$_2$ Authors: Farzaneh Hoveyda-Marashi (1,2), Xuefei Guo (1,2), Caitlin Kengle (1,2), Camille Bernal-Choban (1,2), Yue Su (1,2), Jin Chen (1,2), Dipanjan Chaudhuri (1,2), Peter Abbamonte (1,2) ((1) Department of Physics, University of Illinois, (2) Materials Research Laboratory, University of Illinois) View PDF HTML (experimental) Abstract: We use momentum-resolved electron energy-loss spectroscopy (M-EELS) to study the low-energy charge excitations of 1$T$-TaS$_2$ across the nearly commensurate-to-commensurate charge-density-wave (CDW) transition. Single-crystal x-ray diffraction and elastic M-EELS measurements confirm the expected rotation of the CDW wave vector upon entering the commensurate phase. In the nearly commensurate phase, the low-energy M-EELS spectra reveal an acoustic phonon branch and two optical phonon features whose energies and dispersions are broadly consistent with previous calculations and inelastic x-ray measurements. Across the transition, the optical phonon energies remain nearly unchanged, while their spectral intensity develops a pronounced temperature dependence near the CDW ordering wave vector. At higher energies, the finite-momentum charge response undergoes a substantial redistribution of spectral weight below the transition, consistent with the opening of an energy gap. These results demonstrate that M-EELS provides simultaneous access to lattice dynamics and finite-momentum valence band charge excitations in 1$T$-TaS$_2$, revealing their evolution across the commensurate CDW transition. Subjects: Strongly Correlated Electrons (cond-mat.str-el) Cite as: arXiv:2608.23492 [cond-mat.str-el] (or arXiv:2608.23492v2 [cond-mat.str-el] for this version) https://doi.org/10.48550/arXiv.2608.23492 Focus to learn more arXiv-issued DOI via DataCite Submission history From: Farzaneh Hoveyda-Marashi [ view email ] [v1] Mon, 24 Aug 2026 16:54:50 UTC (6,328 KB) [v2] Wed, 26 Aug 2026 18:51:50 UTC (6,328 KB) Full-text links: Access Paper: View PDF HTML (experimental) TeX Source view license Current browse context: cond-mat.str-el < prev | next > new | recent | 2026-08 Change to browse by: cond-mat References & Citations SciX Google Scholar Semantic Scholar export BibTeX citation Bookmark Bibliographic Tools Bibliographic and Citation Tools Bibliographic Explorer Toggle Bibliographic Explorer ( What is the Explorer? ) Connected Papers Toggle Connected Papers ( What is Connected Papers? ) Litmaps Toggle Litmaps ( What is Litmaps? ) scite.ai Toggle scite Smart Citations ( What are Smart Citations? ) Code, Data, Media Code, Data and Media Associated with this Article alphaXiv Toggle alphaXiv ( What is alphaXiv? ) Links to Code Toggle CatalyzeX Code Finder for Papers ( What is CatalyzeX? ) DagsHub Toggle DagsHub ( What is DagsHub? ) GotitPub Toggle Gotit.pub ( What is GotitPub? ) Huggingface Toggle Hugging Face ( What is Huggingface? ) ScienceCast Toggle ScienceCast ( What is ScienceCast? ) Demos Demos Replicate Toggle Replicate ( What is Replicate? ) Spaces Toggle Hugging Face Spaces ( What is Spaces? ) Spaces Toggle TXYZ.AI ( What is TXYZ.AI? ) Related Papers Recommenders and Search Tools Link to Influence Flower Influence Flower ( What are Influence Flowers? ) Core recommender toggle CORE Recommender ( What is CORE? ) IArxiv recommender toggle IArxiv Recommender ( What is IArxiv? ) Author Venue Institution Topic About arXivLabs arXivLabs: experimental projects with community collaborators arXivLabs is a framework that allows collaborators to develop and share new arXiv features directly on our website. Both individuals and organizations that work with arXivLabs have embraced and accepted our values of openness, community, excellence, and user data privacy. arXiv is committed to these values and only works with partners that adhere to them. Have an idea for a project that will add value for arXiv's community? Learn more about arXivLabs . Which authors of this paper are endorsers? | Disable MathJax ( What is MathJax? ) We gratefully acknowledge support from our major funders , member institutions , and all contributors. About · Help · Contact · Subscribe · Copyright · Privacy · Accessibility · Operational Status (opens in new tab)

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