Absence of Critical Thickness in an Ultrathin Improper Ferroelectric Film

Na Sai, Craig J. Fennie, and Alexander A. Demkov
Phys. Rev. Lett. 102, 107601 – Published 11 March 2009


We study the ferroelectric stability and surface structural properties of an oxygen-terminated hexagonal YMnO3 ultrathin film using density functional theory. Under an open circuit boundary condition, the ferroelectric state with the spontaneous polarization normal to the (0001) surface is found to be metastable in a single domain state despite the presence of a depolarizing field. Our results highlight that improper ferroelectric ultrathin films can have rather unique properties that are distinct from those of very thin films of ordinary ferroelectrics.

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  • Received 19 August 2008


©2009 American Physical Society

Authors & Affiliations

Na Sai1,2, Craig J. Fennie3, and Alexander A. Demkov1

  • 1Department of Physics, The University of Texas at Austin, Austin, Texas 78712, USA
  • 2Center for Computational Materials, Institute for Computational Engineering and Sciences, The University of Texas, Austin, Texas 78712, USA
  • 3School of Applied and Engineering Physics, Cornell University, Ithaca, New York 14853, USA

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Vol. 102, Iss. 10 — 13 March 2009

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