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Second-principles lattice models have recently enabled large-scale simulations of complex polar textures in ferroelectric perovskite oxides, including vortices, skyrmions, merons and related inhomogeneous domain structures [1-3]. In displacive compounds, it is known that extra charge can induce local tuning of displacive motions, being for instance at the origin of anti-distortive polarons [4]. It might therefore be questioned if, reciprocally, the intrinsic inhomogeneity of distortions inherent to polar textures can locally tune the electronic properties and produce unexpected phenomena.
In practice, the electronic properties of large-scale systems are hardly accessible from first-principles calculations while second-principles lattice models integrate out the electronic degrees of freedom, so preventing direct access to them. To overcome this limitation, a methodology has been proposed to explicitly and self-consistently reintroduce selected electronic degrees of freedom within pre-existing lattice models [5,6]. Following this methodology, we report the construction of a Wannier-based second-principles electronic model for BaTiO₃ from first-principles calculations. We benchmark its accuracy against reference first-principles calculations across multiple structural configurations, including both pristine and doped systems, using the electronic band structure as the primary metric
Subsequently, we combine this electronic model with its lattice counterpart to explore the electronic properties of nanoscale topological textures in BaTiO₃. Focusing on topologically non-trivial polar textures obtained from the corresponding lattice model [2,3], we analyze how these inhomogeneous polar distortions reshape the local electronic structure.
Binayak Mukherjee was supported by IPD-STEMA grant from the University of Liege.
References:
[1] J. Junquera, et al, “Topological phases in polar oxide nanostructures,” Rev. Mod. Phys. 95, 025001 (2023).
[2] L. Bastogne, F. Gomez-Ortiz, S. Anand and Ph. Ghosez, Dynamical manipulation of polar topologies from acoustic phonon excitations, Nano Lett. 24, 13783 (2024).
[3] F. Gómez-Ortiz, L. Bastogne, S. Anand, M. Yu, X. He, and P. Ghosez, “Switchable skyrmion – antiskyrmion tubes in rhombohedral BaTiO₃ and related materials,” Phys. Rev. B 111, L180104 (2025).
[4] H. Hassani, E. Bousquet, X. He, B. Partoens, and P. Ghosez, “The anti-distortive polaron as an alternative mechanism for lattice-mediated charge trapping,” Nat. Commun. 16, 1688 (2025).
[5] P. García-Fernández, J. C. Wojdeł, J. Íñiguez, and J. Junquera, “Second-principles method for materials simulations including electron and lattice degrees of freedom,” Phys. Rev. B 93, 195137 (2016).
[6] N. Carral-Sainz, T. Fernández-Ruiz, J. Íñiguez-González, J. Junquera, and P. García-Fernández, “Systematic generation of electron models for second-principles density functional theory methods,” Phys. Rev. B 112, 155146 (2025).
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