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Signatures of Ultrafast Reversal of Excitonic Order in Ta₂NiSe₅

Ning, H. and Mehio, O. and Buchhold, M. and Kurumaji, T. and Refael, G. and Checkelsky, J. G. and Hsieh, D. (2020) Signatures of Ultrafast Reversal of Excitonic Order in Ta₂NiSe₅. Physical Review Letters, 125 (26). Art. No. 267602. ISSN 0031-9007. doi:10.1103/physrevlett.125.267602.

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In the presence of electron-phonon coupling, an excitonic insulator harbors two degenerate ground states described by an Ising-type order parameter. Starting from a microscopic Hamiltonian, we derive the equations of motion for the Ising order parameter in the phonon coupled excitonic insulator Ta₂NiSe₅ and show that it can be controllably reversed on ultrashort timescales using appropriate laser pulse sequences. Using a combination of theory and time-resolved optical reflectivity measurements, we report evidence of such order parameter reversal in Ta₂NiSe₅ based on the anomalous behavior of its coherently excited order-parameter-coupled phonons. Our Letter expands the field of ultrafast order parameter control beyond spin and charge ordered materials.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper InCaltech News
Buchhold, M.0000-0001-5194-9388
Kurumaji, T.0000-0002-2157-3727
Checkelsky, J. G.0000-0003-0325-5204
Hsieh, D.0000-0002-0812-955X
Alternate Title:Signatures of Ultrafast Reversal of Excitonic Order in Ta2NiSe5
Additional Information:© 2020 American Physical Society. (Received 15 June 2020; revised 25 August 2020; accepted 24 November 2020; published 22 December 2020) We thank Rick Averitt, Edoardo Baldini, Swati Chaudhary, Nuh Gedik, Xinwei Li, Tianwei Tang, and Alfred Zong for useful discussions. D. H. and J. G. C. acknowledge support from the DARPA DRINQS program (Grant No. D18AC00014). D. H. also acknowledges support for instrumentation from the Institute for Quantum Information and Matter, a NSF Physics Frontiers Center (PHY-1733907). M. B. acknowledges the support from the Department of Energy under Award No. DE-SC0019166. T. K. acknowledges the support by the Yamada Science Foundation Fellowship for Research Abroad and JSPS Overseas Research Fellowships.
Group:Institute for Quantum Information and Matter
Funding AgencyGrant Number
Defense Advanced Research Projects AgencyD18AC00014
Institute for Quantum Information and Matter (IQIM)UNSPECIFIED
Department of Energy (DOE)DE-SC0019166
Yamada Science FoundationUNSPECIFIED
Japan Society for the Promotion of Science (JSPS)UNSPECIFIED
Issue or Number:26
Record Number:CaltechAUTHORS:20201224-090002408
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:107284
Deposited By: George Porter
Deposited On:04 Jan 2021 16:37
Last Modified:28 Feb 2023 19:39

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