From: David Vanderbilt <dhv@physics.rutgers.edu> Date (v1): Tue, 9 Oct 2001 19:25:59 GMT (160kb) Date (revised v2): Fri, 18 Jan 2002 18:55:41 GMT (155kb)
Authors:
Lixin He,
J.B. Neaton,
Morrel H. Cohen,
David Vanderbilt (Department of Physics and Astronomy, Rutgers University),
C.C. Homes (Department of Physics, Brookhaven National Laboratory)
Comments: 12 pages, with 4 postscript figures embedded. Uses REVTEX and epsf
macros. Also available at
this http URL
Subj-class: Materials Science
Structural and electronic properties of CaCu{3}Ti{4}O{12} have been calculated using density-functional theory within the local spin-density approximation. After an analysis of structural stability, zone-center optical phonon frequencies are evaluated using the frozen-phonon method, and mode effective charges are determined from computed Berry-phase polarizations. Excellent agreement between calculated and measured phonon frequencies is obtained; calculated mode effective charges are in poorer agreement with experiment, although they are of the correct order of magnitude; and the lattice contribution to the static dielectric constant is calculated to be ~40. On the basis of these results, various mechanisms are considered for the enormous dielectric response reported in recent experiments. No direct evidence is found for intrinsic lattice or electronic mechanisms, suggesting that increased attention should be given to extrinsic effects.