Surface Effects in Ferroelectrics: Periodic Slab Computations for BaTiO_3
Abstract
Description
Total energies, electronic structure, surface energies, polarization, potentials and charge densities were studied for slabs of BaTiO_3 using the Linearized Augmented Plane Wave (LAPW) method. The depolarization field inhibits ferroelectricity in the slabs, and the macroscopic field set up across a ferroelectric slab is sufficient to cause electronic states to span the gap and give a metallic band structure, but the band shifts are not rigid and O p states tend to pile up at the Fermi level. There are electronic surface states, especially evident on TiO_2 surfaces. The dangling bonds bond back to the surface Ti's and make the surface stable and reactive. The BaO surfaces are more ionic than the bulk.
19 pages, revtex, 11 figures, proceedings of the Fourth Williamsburg Workshop on First-Principles Calculations for Ferroelectrics, to appear in Ferroelectrics
19 pages, revtex, 11 figures, proceedings of the Fourth Williamsburg Workshop on First-Principles Calculations for Ferroelectrics, to appear in Ferroelectrics