Abstract
A first-principles-based approach is developed and used to investigate ultrathin films having different growth directions and subject to different boundary conditions. A wide variety of dipole patterns is found, including ferroelectric phases absent in the bulk and different periodic stripe nanodomains. Moreover, a large enhancement of dielectricity is found in ultrathin films exhibiting a growth direction that differs from a possible direction of the polarization in the corresponding bulk. A set of two general and simple rules is provided to analyze and understand all these features.
- Received 26 June 2006
DOI:https://doi.org/10.1103/PhysRevB.74.064102
©2006 American Physical Society