Scanning Tunneling Microscopy Observation of Phonon Condensate
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:
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[1]
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[2]
; [1]
; [1]
; [3]
; [3]
- Air Force Research Lab. (AFRL), Wright-Patterson AFB, OH (United States)
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
- Pennsylvania State Univ., University Park, PA (United States)
- Publication Date:
- Report Number(s):
- LA-UR-17-22298
Journal ID: ISSN 2045-2322
- Grant/Contract Number:
- AC52-06NA25396
- Type:
- Accepted Manuscript
- Journal Name:
- Scientific Reports
- Additional Journal Information:
- Journal Volume: 7; Journal ID: ISSN 2045-2322
- Publisher:
- Nature Publishing Group
- Research Org:
- Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
- Sponsoring Org:
- USDOE
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 36 MATERIALS SCIENCE; Material Science; Bose–Einstein condensatesTwo-dimensional materials
- OSTI Identifier:
- 1357137
- Free Publicly Accessible Full Text
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Accepted Manuscript (DOE)
- Publisher's Version of Record
- https://doi.org/10.1038/srep43214