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Phys. Rev. B 70, 054103 (2004) [5 pages]

Atomistic simulations of the incipient ferroelectric KTaO3

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A. R. Akbarzadeh1, L. Bellaiche1, Kevin Leung2, Jorge Íñiguez3,4,5, and David Vanderbilt3
1Physics Department, University of Arkansas, Fayetteville, Arkansas 72701, USA
2Sandia National Laboratories, Mail Stop 1421, Albuquerque, New Mexico 87185, USA
3Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854-8019, USA
4NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-8562, USA
5Department of Materials Science and Engineering, University of Maryland, College Park, Maryland 20742-2115, USA

Received 22 December 2003; published 17 August 2004

A parameterized effective Hamiltonian approach is used to investigate KTaO3. We find that the experimentally observed anomalous dielectric response of this incipient ferroelectric is well reproduced by this approach, once quantum effects are accounted for. Quantum fluctuations suppress the paraelectric-to-ferroelectric phase transition; it is unnecessary to introduce defects to explain the dielectric behavior. The resulting quantum-induced local structure exhibits off-center atomic displacements that display longitudinal, needle-like correlations extending a few lattice constants.

© 2004 The American Physical Society

URL:
http://link.aps.org/doi/10.1103/PhysRevB.70.054103
DOI:
10.1103/PhysRevB.70.054103
PACS:
77.84.−s, 78.20.Bh, 81.30.Dz
 
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