Finite Electron Temperature Density Functional Theory and Neural Network Molecular Dynamics study of Sub Pico-Second Optical Control of Ferroelectric Domains in PbTiO<sub>3</sub> based Nanostructuress
ORAL
Abstract
Two temperature molecular dynamics based on finite electron temperature density functional theory (FT-DFT) has been successful in modeling optical excitation in materials as repopulation of the Fermi-Dirac distribution due to strong electron-field interactions. We employ FT-DFT based molecular dynamics to study the ferroelectric perovskite PbTiO3 and find photo-induced charge transfer activation of optical phonons leads to a sub picosecond tetragonal/ferroelectric to cubic/paraelectric structural phase transition at 300K in the bulk structure. To study large polar domains common in PbTiO3 based nanostructures we developed a neural-network force-field model based on ground state DFT and FT-DFT training data. Applications of the model to study polar vortex formation, domain wall structure, and their interactions in PbTiO3 based nanostructures will be discussed.
*This work was supported as part of the Computational Materials Sciences Program funded by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, under Award Number DE-SC0014607.
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Presenters
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Thomas Linker
- Collaboratory for Advanced Computing and Simulations, University of Southern California
- Univ of Southern California