About this Abstract |
| Meeting |
2027 TMS Annual Meeting & Exhibition
|
| Symposium
|
Computational Thermodynamics and Kinetics
|
| Presentation Title |
Temperature-Aware Dimer Method for Diffusion Transition States in Strongly Anharmonic Solids |
| Author(s) |
Sara Kadkhodaei, Seyyedfaridoddin Fattahpour |
| On-Site Speaker (Planned) |
Sara Kadkhodaei |
| Abstract Scope |
Conventional saddle-point searches based on zero-temperature potential energy surfaces (PES) become inadequate for strongly anharmonic materials at finite temperature. Here, I introduce the temperature-aware dimer (TAD) method, a saddle-point search framework that samples and navigates the finite-temperature energy landscape toward diffusion transition states. TAD couples dimer with a nested Gaussian Process Regression (GPR): a local GPR learns the energy surface from atomic vibrations, while a global GPR smooths the coarse-grained landscape from local GPRs to guide dimer motion. I demonstrate TAD on strongly anharmonic, dynamically stabilized bcc Zr and cubic ZrO₂ with zero-temperature lattice instabilities, as well as mechanically stable bcc Mo, showing good agreement with molecular dynamics simulations and experiments. A spectrum of diffusive barriers is revealed by canonical TAD trajectories, capturing temperature- and anharmonicity-dependent dynamical fluctuations that are distinct from, yet conceptually analogous to, the chemical fluctuations that govern barrier variability in chemically complex materials. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Computational Materials Science & Engineering, Modeling and Simulation, Other |