Finite-Temperature Ferroelectric Phase Transitions from Machine-Learned Force Fields

Fuente: arXiv
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Main Authors: Eggestad, Kristoffer, Skogvoll, Ida C., Gullbrekken, Øystein, Williamson, Benjamin A. D., Selbach, Sverre M.
Format: Preprint
Published: 2025
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author Eggestad, Kristoffer
Skogvoll, Ida C.
Gullbrekken, Øystein
Williamson, Benjamin A. D.
Selbach, Sverre M.
author_facet Eggestad, Kristoffer
Skogvoll, Ida C.
Gullbrekken, Øystein
Williamson, Benjamin A. D.
Selbach, Sverre M.
contents Simulating finite temperature phase transitions from first-principles is computationally challenging. Recently, molecular dynamics (MD) simulations using machine-learned force fields (MLFFs) have opened a new avenue for finite-temperature calculations with near-first-principles accuracy. Here we use MLFFs, generated using on-the-fly training, to investigate structural phase transitions in four of the most well-studied ferroelectric oxides; BaTiO$_3$, PbTiO$_3$, LiNbO$_3$ and BiFeO$_3$. Only using the 0 K ground state structure as input for the training, the resulting MLFFs can qualitatively predict all the main structural phases and phase transitions, while the quantitative results are sensitive to the choice of exchange correlation functional with PBEsol found to be more robust than LDA and r$^2$SCAN. MD simulations also reproduce the experimentally observed order-disorder character of Ti displacements in BaTiO$_3$, the abrupt first order transitions of BiFeO$_3$ and PbTiO$_3$, and the mixed order-disorder and displacive character of the ferroelectric transition in LiNbO$_3$. Finally, we discuss the potential and limitations of using MLFFs for simulating ferroelectric phase transitions.
format Preprint
id arxiv_https___arxiv_org_abs_2510_25439
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Finite-Temperature Ferroelectric Phase Transitions from Machine-Learned Force Fields
Eggestad, Kristoffer
Skogvoll, Ida C.
Gullbrekken, Øystein
Williamson, Benjamin A. D.
Selbach, Sverre M.
Materials Science
Simulating finite temperature phase transitions from first-principles is computationally challenging. Recently, molecular dynamics (MD) simulations using machine-learned force fields (MLFFs) have opened a new avenue for finite-temperature calculations with near-first-principles accuracy. Here we use MLFFs, generated using on-the-fly training, to investigate structural phase transitions in four of the most well-studied ferroelectric oxides; BaTiO$_3$, PbTiO$_3$, LiNbO$_3$ and BiFeO$_3$. Only using the 0 K ground state structure as input for the training, the resulting MLFFs can qualitatively predict all the main structural phases and phase transitions, while the quantitative results are sensitive to the choice of exchange correlation functional with PBEsol found to be more robust than LDA and r$^2$SCAN. MD simulations also reproduce the experimentally observed order-disorder character of Ti displacements in BaTiO$_3$, the abrupt first order transitions of BiFeO$_3$ and PbTiO$_3$, and the mixed order-disorder and displacive character of the ferroelectric transition in LiNbO$_3$. Finally, we discuss the potential and limitations of using MLFFs for simulating ferroelectric phase transitions.
title Finite-Temperature Ferroelectric Phase Transitions from Machine-Learned Force Fields
topic Materials Science
url https://arxiv.org/abs/2510.25439