Prediction and observation of intermodulation sidebands from anharmonic phonons in NaBr
Abstract
A quantum Langevin model, like models from optomechanics, was developed for phonons. It predicts intermodulation phonon sidebands (IPSs) in anharmonic crystals. Ab initio calculations of anharmonic phonons in rock-salt NaBr showed these spectral features as many-body effects. Modern inelastic neutron scattering measurements on a crystal of NaBr at 300 K revealed diffuse intensity at high phonon energy from a predicted upper IPS. The transverse optical (TO) part of the new features originates from phonon intermodulation between the transverse acoustic (TA) and TO phonons. The longitudinal optical spectral features originate from three-phonon coupling between the TA modes and the TO lattice modes. The partner lower IPS proves to be an intrinsic localized mode. Interactions with the thermal bath broaden and redistribute the spectral weight of the IPS pair. These sidebands are a probe of the anharmonicity and quantum noise of phonons in NaBr and suggest novel interactions between photons and phonons.
Additional Information
© 2021 American Physical Society. Received 14 November 2020; accepted 16 March 2021; published 12 April 2021. We thank O. Hellman, K. Vahala, and F. Yang for helpful discussions. Research at the Spallation Neutron Source (SNS) and the High Flux Isotope Reactor (HFIR) at the Oak Ridge National Laboratory was sponsored by the Scientific User Facilities Division, Basic Energy Sciences (BES), Department of Energy (DOE). M.E.M. was supported by the US Department of Energy, Office of Science, Office of Basic Energy Sciences, Materials Sciences and Engineering Division under Contract No. DE-AC05-00OR22725. This paper used resources from National Energy Research Scientific Computing Center (NERSC), a DOE Office of Science User Facility supported by the Office of Science of the US Department of Energy under Contract No. DE-AC02-05CH11231. This paper was supported by the DOE Office of Science, BES, under Contract No. DE-FG02-03ER46055.Attached Files
Published - PhysRevB.103.134302.pdf
Accepted Version - 2011.04842.pdf
Supplemental Material - Supplemental_Shen_PhononSidebands_NaBr.pdf
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Additional details
- Alternative title
- Prediction and Observation of Intermodulation Sidebands from Anharmonic Phonons
- Eprint ID
- 108782
- Resolver ID
- CaltechAUTHORS:20210421-095643731
- DE-AC05-00OR22725
- Department of Energy (DOE)
- DE-AC02-05CH11231
- Department of Energy (DOE)
- DE-FG02-03ER46055
- Department of Energy (DOE)
- Created
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2021-04-21Created from EPrint's datestamp field
- Updated
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2021-04-21Created from EPrint's last_modified field