About this Abstract |
Meeting |
2022 TMS Annual Meeting & Exhibition
|
Symposium
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Computational Thermodynamics and Kinetics
|
Presentation Title |
NOW ON-DEMAND ONLY - Modeling Anharmonicity with Many-body Perturbation Theory and Machine Learning Potentials in Cu2O |
Author(s) |
Claire N. Saunders, Dennis Kim, Olle Hellman, Hillary Smith, Camille Bernal, Vladimir Ladygin, Brent Fultz |
On-Site Speaker (Planned) |
Claire N. Saunders |
Abstract Scope |
We report large anharmonicity of optical phonons in cuprite (Cu2O) and unexplained diffuse intensities in the experimental phonon spectrum. Phonon dispersions were measured on a single crystal of cuprite by inelastic neutron scattering from 10 K to 900 K on the ARCS spectrometer at Oak Ridge National Laboratory. Higher-order force constants calculated with a perturbative ab initio effective potential method predicted thermal expansion and other temperature-dependent phonon behaviors. While high-order force constants were more effective than low-order in predicting the observed temperature-dependent phonon behavior, none of the calculations sufficiently accounted for an observed diffuse intensity in the measured phonon spectrum. To model the diffuse spectral intensity, classical molecular dynamics with machine learning interatomic potentials models will be compared with perturbative anharmonic calculations and experimental data. A local dynamics model will be proposed to explain this diffuse inelastic scattering, analogous to phase noise in oscillators. |
Proceedings Inclusion? |
Planned: |
Keywords |
Computational Materials Science & Engineering, Machine Learning, High-Temperature Materials |