Condensed Matter, abstract
cond-mat/0204497

From: Jorge Iniguez <jiniguez@physics.rutgers.edu>
Date: Tue, 23 Apr 2002 14:43:16 GMT   (17kb)

First-principles study of the temperature-pressure phase diagram of BaTiO3

Authors: Jorge Iniguez, D. Vanderbilt (Department of Physics and Astronomy, Rutgers University)
Comments: 4 pages with 4 postscript figures embedded. Uses REVTeX4. Also available at this http URL
Subj-class: Materials Science

We investigate the temperature-pressure phase diagram of BaTiO_3 using a first-principles effective-Hamiltonian approach. We find that the zero-point motion of the ions affects the form of the phase diagram dramatically. Specifically, when the zero-point fluctuations are included in the calculations, all the polar (tetragonal, orthorhombic, and rhombohedral) phases of BaTiO_3 survive down to 0 K, while only the rhombohedral phase does otherwise. We provide a simple explanation for this behavior. Our results confirm the essential correctness of the phase diagram proposed by Ishidate et al. (Phys. Rev. Lett. 78, 2397 (1997)).

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