2002/05/21 by Na Sai, Karin M. Rabe, David Vanderbilt
Earth and Planetary Sciences · Materials Science · Physics and Astronomy · #Ferroelectric and Piezoelectric Materials #High-pressure geophysics and materials #Photorefractive and Nonlinear Optics #cond-mat.mtrl-sci
paper · pdf · doi:10.1103/physrevb.66.104108
published as Phys. Rev. B 66, 104108 (2002) · 19 pages, with 15 postscript figures embedded. Uses REVTEX4 and epsf macros. Also available at http://www.physics.rutgers.edu/~dhv/preprints/sai_pol/index.html
arxiv created 2002/05/21 · openalex publication_date 2002/09/30 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28
We have developed and implemented a formalism for computing the structural response of a periodic insulating system to a homogeneous static electric field within density-functional perturbation theory (DFPT). We consider the thermodynamic potentials E(R,\ensuremathη,E) and F(R,\ensuremathη,P), whose minimization with respect to the internal structural parameters R and unit cell strain \ensuremathη yields the equilibrium structure at fixed electric field E and polarization P, respectively. First-order expansion of E(R,\ensuremathη,E) in E leads to a useful approximation in which R(P) and \ensuremathη(P) can be obtained by simply minimizing the zero-field internal energy with respect to structural coordinates subject to the constraint of a fixed spontaneous polarization P. To facilitate this minimization, we formulate a modified DFPT scheme such that the computed derivatives of the polarization are consistent with the discretized form of the Berry-phase expression. We then describe the application of this approach to several problems associated with bulk and short-period superlattice structures of ferroelectric materials such as BaTiO3 and PbTiO3. These include the effects of compositionally broken inversion symmetry, the equilibrium structure for high values of polarization, field-induced structural phase transitions, and the lattice contributions to the linear and the nonlinear dielectric constants.