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Title: Scanning Tunneling Microscopy Observation of Phonon Condensate

Abstract

Using quantum tunneling of electrons into vibrating surface atoms, phonon oscillations can be observed on the atomic scale. Phonon interference patterns with unusually large signal amplitudes have been revealed by scanning tunneling microscopy in intercalated van der Waals heterostructures. Our results show that the effective radius of these phonon quasi-bound states, the real-space distribution of phonon standing wave amplitudes, the scattering phase shifts, and the nonlinear intermode coupling strongly depend on the presence of defect-induced scattering resonance. The observed coherence of these quasi-bound states most likely arises from phase- and frequency-synchronized dynamics of all phonon modes, and indicates the formation of many-body condensate of optical phonons around resonant defects. We found that increasing the strength of the scattering resonance causes the increase of the condensate droplet radius without affecting the condensate fraction inside it. The condensate can be observed at room temperature.

Authors:
 [1]; ORCiD logo [2];  [1];  [1];  [3];  [3]
  1. Air Force Research Lab. (AFRL), Wright-Patterson AFB, OH (United States)
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
  3. Pennsylvania State Univ., University Park, PA (United States)
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1357137
Report Number(s):
LA-UR-17-22298
Journal ID: ISSN 2045-2322
Grant/Contract Number:
AC52-06NA25396
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Scientific Reports
Additional Journal Information:
Journal Volume: 7; Journal ID: ISSN 2045-2322
Publisher:
Nature Publishing Group
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; Material Science; Bose–Einstein condensatesTwo-dimensional materials

Citation Formats

Altfeder, Igor, Balatsky, Alexander V., Voevodin, Andrey A., Check, Michael H., Eichfeld, Sarah M., and Robinson, Joshua A. Scanning Tunneling Microscopy Observation of Phonon Condensate. United States: N. p., 2017. Web. doi:10.1038/srep43214.
Altfeder, Igor, Balatsky, Alexander V., Voevodin, Andrey A., Check, Michael H., Eichfeld, Sarah M., & Robinson, Joshua A. Scanning Tunneling Microscopy Observation of Phonon Condensate. United States. doi:10.1038/srep43214.
Altfeder, Igor, Balatsky, Alexander V., Voevodin, Andrey A., Check, Michael H., Eichfeld, Sarah M., and Robinson, Joshua A. Wed . "Scanning Tunneling Microscopy Observation of Phonon Condensate". United States. doi:10.1038/srep43214. https://www.osti.gov/servlets/purl/1357137.
@article{osti_1357137,
title = {Scanning Tunneling Microscopy Observation of Phonon Condensate},
author = {Altfeder, Igor and Balatsky, Alexander V. and Voevodin, Andrey A. and Check, Michael H. and Eichfeld, Sarah M. and Robinson, Joshua A.},
abstractNote = {Using quantum tunneling of electrons into vibrating surface atoms, phonon oscillations can be observed on the atomic scale. Phonon interference patterns with unusually large signal amplitudes have been revealed by scanning tunneling microscopy in intercalated van der Waals heterostructures. Our results show that the effective radius of these phonon quasi-bound states, the real-space distribution of phonon standing wave amplitudes, the scattering phase shifts, and the nonlinear intermode coupling strongly depend on the presence of defect-induced scattering resonance. The observed coherence of these quasi-bound states most likely arises from phase- and frequency-synchronized dynamics of all phonon modes, and indicates the formation of many-body condensate of optical phonons around resonant defects. We found that increasing the strength of the scattering resonance causes the increase of the condensate droplet radius without affecting the condensate fraction inside it. The condensate can be observed at room temperature.},
doi = {10.1038/srep43214},
journal = {Scientific Reports},
number = ,
volume = 7,
place = {United States},
year = {Wed Feb 22 00:00:00 EST 2017},
month = {Wed Feb 22 00:00:00 EST 2017}
}

Journal Article:
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