About this Abstract |
Meeting |
2023 TMS Annual Meeting & Exhibition
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Symposium
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Neutron and X-ray Scattering in Materials Science
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Presentation Title |
Inelastic Neutron Scattering Studies of New Spectral Features from Nonlinear Phonon Interactions |
Author(s) |
Brent T. Fultz, Vladimir Ladygin, Camille Bernal-Choban, Claire Saunders, Yang Shen |
On-Site Speaker (Planned) |
Brent T. Fultz |
Abstract Scope |
Especially at high temperatures, "anharmonicity'' alters the phonon entropy, free energy, and thermophysical properties such as thermal expansion[1]. Large anharmonicity with nonlinear phonon interactions can bring new features to phonon spectra. Intermodulation phonon sidebands were recently observed by inelastic neutron scattering in NaBr at 300 K[2]. In a crystal of NaBr, the lower sideband is an intrinsic localized mode, previously observed by Manley. The newly-discovered upper sideband completes the picture for flat phonon branches. Higher temperatures may show intermodulations between dispersive phonon branches. Another newly-observed effect of anharmonicity is diffuse inelastic intensity (DII) in the INS phonon spectra of cuprite, Cu2</SIB>O. Today we can say that the DII reflects changes in the dynamics of both Cu and O atoms on a time scale on the order of their vibrational periods.
[1] DOI: 10.1103/PhysRevLett.125.085504. [2] DOI: 10.1103/PhysRevB.103.134302.
This work is supported by DOE BES award No. DE-FG02-03ER46055. |
Proceedings Inclusion? |
Planned: |
Keywords |
Characterization, Computational Materials Science & Engineering, Other |