Signatures of Ultrafast Reversal of Excitonic Order in Ta₂NiSe₅
Abstract
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.
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.Attached Files
Published - PhysRevLett.125.267602.pdf
Accepted Version - 2012.12912.pdf
Supplemental Material - ARR_Ning_8-24-2020_SI.pdf
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Additional details
- Alternative title
- Signatures of Ultrafast Reversal of Excitonic Order in Ta2NiSe5
- Eprint ID
- 107284
- Resolver ID
- CaltechAUTHORS:20201224-090002408
- Defense Advanced Research Projects Agency
- D18AC00014
- Institute for Quantum Information and Matter (IQIM)
- NSF
- PHY-1733907
- Department of Energy (DOE)
- DE-SC0019166
- Yamada Science Foundation
- Japan Society for the Promotion of Science (JSPS)
- Created
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2021-01-04Created from EPrint's datestamp field
- Updated
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2023-02-28Created from EPrint's last_modified field
- Caltech groups
- Institute for Quantum Information and Matter