# Electronic structures and lattice dynamics of BaTiO3 and BiFeO3 : a comparative first-principles study

**Authors:** Hong-Jian Feng  
**arXiv:** [0711.3942](https://arxiv.org/abs/0711.3942)  
**Date:** 2007-11-26  
**Summary page:** https://www.summarizepaper.com/en/paper/0711.3942v3/

## Key points

- Study by Hong-Jian Feng focuses on electronic structures and lattice dynamics of BaTiO3 and BiFeO3
- Research uses first-principles calculations with density functional theory and perturbation theory
- Highlights role of Ti-O and Bi-O bonds in stabilizing distorted structure
- Reveals spontaneous polarization values: 59.4 μC/cm2 for BiFeO3, 27.6 μC/cm2 for BaTiO3
- BiFeO3's ferroelectricity driven by stereochemical activity of Bi-6s long-pair
- Predicts potential for new multiferroic perovskite-type materials combining properties of BaTiO3 and BiFeO3 to exhibit improved ferromagnetic ordering
- Offers insights into fundamental properties and potential applications in technological fields

## Summary

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The study by Hong-Jian Feng delves into the electronic structures and lattice dynamics of barium titanate (BaTiO3) and bismuth ferrite (BiFeO3) through first-principles calculations using density functional theory and density functional perturbation theory. The research focuses on investigating the ferroelectric properties of these materials, as well as analyzing the phonon dispersion of BaTiO3. The results of the study highlight the significant role played by the strong hybridization of Ti-O and Bi-O bonds in stabilizing the distorted structure of both BaTiO3 and BiFeO3. Calculations reveal a spontaneous polarization of 59.4 μC/cm2 for BiFeO3 and 27.6 μC/cm2 for BaTiO3, determined using the berry phase method within the modern theory of polarization. Interestingly, it is observed that the stereochemical activity of Bi-6s long-pair serves as a driving mechanism for ferroelectricity in BiFeO3, leading to a greater polarization compared to the Ti off-centering displacement in BaTiO3. Furthermore, the study predicts that new multiferroic perovskite-type materials combining these two ferroelectric instabilities are likely to exhibit improved ferromagnetic ordering when compared to BiFeO3. This insight opens up possibilities for exploring novel materials with enhanced multifunctional properties, offering potential applications in various technological fields. Overall, this comparative first-principles study provides valuable insights into the fundamental properties and behaviors of BaTiO3 and BiFeO3, shedding light on their potential for advancing research in ferroelectricity and multiferroic materials.