Surface Core-Level Shifts as a Toolbox to Evidence the BaTiO 3 Ferroelectric Phase Transition

• Published in: Journal of physical chemistry. C Vol. 127; no. 51; pp. 24734 - 24741
• Main Authors: Sahu, Amit, Deleuze, Pierre-Marie, Magnan, Hélène, Barbier, Antoine, Li, Zheshen, Bourgeois, Sylvie, Domenichini, Bruno, Dupont, Céline
• Format: Journal Article
• Language: English
• Published: American Chemical Society 16.12.2023
• Subjects: Chemical Sciences
• ISSN: 1932-7447; 1932-7455
• DOI: 10.1021/acs.jpcc.3c07564

We predict by density functional theory (DFT) calculations structural modifications specific of the paraelectric/ferroelectric transition and demonstrate that they can be tracked experimentally by means of photoelectron spectroscopy (PES). For BaTiO3, we evidence that the Ba 4d core-level binding energy shifts conveniently allow tracking of the transition for both approaches. DFT calculations reveal different temperature behaviors for bulk and surface features, which can be experimentally followed by PES thanks to specific core-level shifts. Consistently, our PES data show that such modifications occur at a temperature close to the ferroelectric (P4mm) → paraelectric (Pm3m) phase transition of BaTiO3. We thus demonstrate that a fine PES investigation of the electronic structure can be used to evidence a ferroelectric-to-paraelectric phase transition. These results are believed to be general for ferroelectric surfaces, and it is shown that this approach is applicable to other ferroelectric titanate compounds.