Condensed Matter, abstract
cond-mat/0302277
From: David Vanderbilt <dhv@physics.rutgers.edu>
Date: Thu, 13 Feb 2003 22:04:08 GMT (23kb)
First-principles study of (BiScO3){1-x}-(PbTiO3){x} piezoelectric alloys
Authors:
Jorge Iniguez,
David Vanderbilt (Department of Physics and Astronomy, Rutgers University),
L. Bellaiche (Physics Department, University of Arkansas)
Comments: 6 pages, with 3 postscript figures embedded. Uses REVTEX and epsf
macros. Also available at
this http URL
Subj-class: Materials Science
We report a first-principles study of a class of (BiScO3)_{1-x}-(PbTiO3)_x
(BS-PT) alloys recently proposed by Eitel et al. as promising materials for
piezoelectric actuator applications. We show that (i) BS-PT displays very large
structural distortions and polarizations at the morphotropic phase boundary
(MPB) (we obtain a c/a of ~1.05-1.08 and P_tet of ~1.1 C/m^2); (ii) the
ferroelectric and piezoelectric properties of BS-PT are dominated by the onset
of hybridization between Bi/Pb-6p and O-2p orbitals, a mechanism that is
enhanced upon substitution of Pb by Bi; and (iii) the piezoelectric responses
of BS-PT and Pb(Zr_{1-x}Ti_x)O3 (PZT) at the MPB are comparable, at least as
far as the computed values of the piezoelectric coefficient d_15 are concerned.
While our results are generally consistent with experiment, they also suggest
that certain intrinsic properties of BS-PT may be even better than has been
indicated by experiments to date. We also discuss results for PZT that
demonstrate the prominent role played by Pb displacements in its piezoelectric
properties.