Regensburg 2025 – wissenschaftliches Programm
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KFM: Fachverband Kristalline Festkörper und deren Mikrostruktur
KFM 18: Materials Research in Polar Oxides: Perspectives for Optics & Electronics
KFM 18.3: Vortrag
Donnerstag, 20. März 2025, 16:15–16:30, H9
Interaction between small electron-polaron and neutral domain wall in PbTiO3: A DFT+U study — •Mohammad Amirabbasi, Jochen Rohrer, and Karsten Albe — Technical University of Darmstadt, Materials Modelling Division, Otto-Berndt-Straße 3, Darmstadt D-64287, Germany
PbTiO3 is a widely studied ferroelectric material that often requires doping to tailor its electronic structure for specific applications. Understanding charge compensation mechanisms, particularly those mediated by local lattice distortions such as small polarons, is crucial for optimizing these modifications. This research investigates the formation and stability of a small electron polaron in PbTiO3, focusing on its interaction with the neutral 180∘ Pb-centered domain wall using density functional theory with Hubbard corrections (DFT+U). We begin by calculating the formation energy of the 180∘ Pb-centered domain wall. Next, we determine the Born effective charges for various ions and compute the polarization profile across the domain wall. Our results show that the polarization in the bulk region reaches a saturation value, which is in good agreement with experimental measurements. Finally, we calculate the trapping energy of a small electron polaron at Ti centers in both bulk and domain wall regions. The results reveal that the trapping energy is negative in both cases, indicating that small electron polaron formation is energetically favorable. Furthermore, the similarity in trapping energy values suggests that the 180∘ Pb-centered domain wall in PbTiO3 has a minimal impact on this type of small electron polaron formation.
Keywords: Small electron polaron; Neutral domain wall; Trapping energy