| About this Abstract |
| Meeting |
2020 TMS Annual Meeting & Exhibition
|
| Symposium
|
Computational Thermodynamics and Kinetics
|
| Presentation Title |
Phonons at High Pressure in FeTi |
| Author(s) |
Bethuel Khamala, Jorge A. Munoz, Brent Fultz |
| On-Site Speaker (Planned) |
Bethuel Khamala |
| Abstract Scope |
The FeTi system is amenable to computational investigations due to its simple crystal structure and minimalist Fermi surface. A thermally-driven electronic topological transition that results in anomalous phonon softening was recently reported to occur in FeTi at elevated temperatures as new features appear in the Fermi surface and new spanning vectors increase electronic screening of particular phonon modes. Here we report results on the pressure dependence of the spanning vectors, which was investigated using DFT and a neural network to interpolate between k-points. We used the temperature-dependent effective potential (TDEP) methodology to investigate the screening effects on particular modes at high pressure and finite temperature and compared the mode Gruneisen parameters with the phonon dispersions calculated at 0K using atomic displacements. We observe that all phonon modes stiffen, but while the optical M5’ modes stiffen by 50% at a pressure of 47 GPa, the X1 modes stiffen by about 10%. |
| Proceedings Inclusion? |
Planned: Supplemental Proceedings volume |