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Strongly Coupled Electron–Phonon Dynamics in Few-Layer TiSe_2 Exfoliates

Karam, Tony E. and Hu, Jianbo and Blake, Geoffrey A. (2018) Strongly Coupled Electron–Phonon Dynamics in Few-Layer TiSe_2 Exfoliates. ACS Photonics, 5 (4). pp. 1228-1234. ISSN 2330-4022. https://resolver.caltech.edu/CaltechAUTHORS:20180220-084357545

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Abstract

Ultrafast electron diffraction is used to probe the time-resolved dynamics in a few-layer TiSe_2 sample. At normal incidence, the suppression of the Bragg diffraction peak intensities following photoexcitation displays strongly biexponential behavior. For tilted samples, changes in the diffraction peak positions reveal coherent acoustic vibrations that are dependent on the sample thickness and that further permit a calculation of the Young’s modulus. The complex room temperature lattice dynamics observed are attributed to strong electron–phonon coupling and electron–lattice equilibration processes, which support a Jahn–Teller origin of the charge density wave behavior in TiSe_2. Additionally, the significant role that the related Kohn anomalies may play in the electron transport dynamics and transition mechanism of this material is emphasized. These results demonstrate the importance of strongly coupled electron–phonon dynamics in the relaxation of electronically excited room temperature TiSe2, which is expected to impact its applicability in optoelectronics.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1021/acsphotonics.7b00878DOIArticle
https://pubs.acs.org/doi/10.1021/acsphotonics.7b00878PublisherArticle
https://pubs.acs.org/doi/suppl/10.1021/acsphotonics.7b00878PublisherSupporting Information
ORCID:
AuthorORCID
Karam, Tony E.0000-0002-1244-5141
Blake, Geoffrey A.0000-0003-0787-1610
Additional Information:© 2018 American Chemical Society. Received: August 4, 2017; Published: February 7, 2018. Generous financial support for this work was provided by the Gordon and Betty Moore Foundation, as well as the National Science Foundation and the Air Force Office of Scientific Research (grant FA9550-16-1-0200). J.H. acknowledges the support from China 1000-Young Talents Plan. The authors gratefully acknowledge Professor Austin Minnich and Dr. Spencer J. Baskin for valuable discussions, and dedicate this manuscript to the memory of our colleague and mentor Professor Ahmed H. Zewail. Author Contributions: The manuscript was written through contributions of all authors. All authors have given approval to the final version of the manuscript. The authors declare no competing financial interest.
Group:Astronomy Department
Funders:
Funding AgencyGrant Number
Gordon and Betty Moore FoundationUNSPECIFIED
NSFUNSPECIFIED
Air Force Office of Scientific Research (AFOSR)FA9550-16-1-0200
China 1000-Young Talents PlanUNSPECIFIED
Subject Keywords:ultrafast electron diffraction, transition metal dichalcogenides, charge-density waves
Issue or Number:4
Record Number:CaltechAUTHORS:20180220-084357545
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20180220-084357545
Official Citation:Strongly Coupled Electron–Phonon Dynamics in Few-Layer TiSe2 Exfoliates. Tony E. Karam, Jianbo Hu, and Geoffrey A. Blake. ACS Photonics 2018 5 (4), 1228-1234. DOI: 10.1021/acsphotonics.7b00878
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:84886
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:22 Feb 2018 04:48
Last Modified:20 Apr 2020 08:47

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