About this Abstract |
Meeting |
2021 TMS Annual Meeting & Exhibition
|
Symposium
|
Computational Thermodynamics and Kinetics
|
Presentation Title |
A Computational and Experimental Study of Phonon Anharmonicity and Thermal Expansion of Cuprous Oxide |
Author(s) |
Claire N. Saunders, Dennis Kim, Hillary Smith, Brent Fultz |
On-Site Speaker (Planned) |
Claire N. Saunders |
Abstract Scope |
We examine how the quasiharmonic (QH) approximation, which models volume-dependent thermal effects, predicts the thermal expansion of low negative thermal expansion materials like cuprite, Cu2O, but fails to capture the phonon behavior. Phonon dispersions of a single crystal of cuprite were measured on the ARCS spectrometer at ORNL at 10 K and 300 K. Experimental data was folded into an irreducible wedge in the first Brillouin zone, and was subsequently multiphonon scattering and thermal factor corrected. QH calculations and temperature dependent calculations using the stochastic Temperature Dependent Effective Potential (sTDEP) method (QH phonons in an anharmonic potential) were performed at 10, 150, 300, 550 K. Single crystal data will be presented and compared to results from sTDEP calculations. Both computational methods capture the reported experimental thermal expansion, but differ in phonon energy shifts. Broader implications for small negative thermal expansion materials will be discussed. |
Proceedings Inclusion? |
Planned: |