Domain Structure in the Tetragonal Phase of BaTiO3– from Bulk to Nanoparticles

In: Ferroelectrics, Jg. 426 (2012) ; Nr. 1, S. 21-30
ISSN: 0015-0193
Zeitschriftenaufsatz / Fach: Physik
Fakultät für Physik » Theoretische Physik
Abstract:
We present a first-principles density functional theory study of domain wall structures in tetragonal BaTiO3 and its nanoparticles. For the bulk material the domain wall profiles, their width and their formation energy are computed and preliminary investigations on thin BaTiO3 films up to 4 monolayers and small nanoparticles of 15.8 Å have been performed. While the 180° wall is atomically sharp, we find a lower bond for the 90° wall width of 16.5 Å. Although, no ferroelectric state can be stabilized neither in films nor in the nanoparticles of this small size, a large local polarization exits in both cases.