| About this Abstract |
| Meeting |
2020 TMS Annual Meeting & Exhibition
|
| Symposium
|
Computational Thermodynamics and Kinetics
|
| Presentation Title |
Interplay Between Chemical Bonding and Anharmonicity in Cu2O |
| Author(s) |
Claire N. Saunders, Dennis Kim, Olle Hellman, Hillary Smith, Douglas Abernathy, Brent Fultz |
| On-Site Speaker (Planned) |
Claire N. Saunders |
| Abstract Scope |
We calculated and measured strong anharmonicity of the optical phonons in Cuprite, Cu2O. Both the broadenings and shifts of phonon energies cannot be explained by harmonic or quasiharmonic theory. Our ab initio calculations use the stochastic Temperature Dependent Effective Potential (s-TDEP) method to calculate phonon self-energies and spectral functions, which compare directly to experimental dispersions from single crystal inelastic neutron scattering measurements at 10, 300, and 700 K on ARCS at ORNL (post-processed using a data folding method). Thermal broadening of optical dispersions was especially prominent in the experimental data, indicative of a large cubic anharmonicity that is being assessed by s-TDEP. Preliminary calculations correctly show negative thermal expansion, but fail to account for the large thermal broadenings seen at 300 and 700 K. Both effects demonstrate some dependence on the bonding contributions. Broader implications for the interplay between anharmonicity and chemical bonds will be discussed. |
| Proceedings Inclusion? |
Planned: Supplemental Proceedings volume |