Solid State and Optics Seminar

Wednesday, March 29, 2006

1:00 p.m.

107 Mason Lab

"Theory of ferroelectric perovskite ultrathin films and superlattices"

Prof. David Vanderbilt
Rutgers University

Abstract

Advances in epitaxial growth techniques and first-principles theory have recently combined to generate excitement about the possibilities for the design and growth of ultrathin film and superlattice structures composed of ferroelectric, paraelectric, and related perovskite oxides. For example, paraelectric materials can be driven ferroelectric by epitaxial-strain effects; ferroelectric materials can attain higher polarization in ultrathin film form than in bulk; and inversion symmetry can be intentionally broken by an appropriate choice of layer sequences in atomic-layer superlattices, leading to asymmetric ferroelectricity. I will review the theory of these effects, making contact with recent experiments where appropriate. I will end by discussing our work in progress, in which we compute the nonlinear dielectric properties of superlattice structures and attempt to derive predictive models based on the assumption that the polarization of each atomic layer depends only on its local environment.

Host: Sohrab Ismail-Beigi