Ab initio study of the electronic and structural properties of the ferroelectric transition in KH2PO4

Qing Zhang, F. Chen, Nicholas Kioussis, S. G. Demos, and H. B. Radousky
Phys. Rev. B 65, 024108 – Published 19 December 2001
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Abstract

First-principles electronic structure calculations were carried out for the paraelectric and ferroelectric phases of KH2PO4 using the pseudopotential method. The calculated structures are in good agreement with experiment. The calculations reveal that the distance δ between the two equilibrium positions of H along the O-O bond in the paraelectric phase depends on both the O-O bond length and the coordinated motion of the heavier P and K atoms. The results reconcile the previously proposed tunneling and geometric phenomenological models. The spontaneous polarization is found to arise from the redistribution of charge density caused by the displacement of the P atoms relative to the O atoms along the ferroelectric axis. The critical pressure for the transition from the orthorhombic to the tetragonal structure at zero temperature is found to be 30 kbar.

  • Received 10 April 2001

DOI:https://doi.org/10.1103/PhysRevB.65.024108

©2001 American Physical Society

Authors & Affiliations

Qing Zhang, F. Chen, and Nicholas Kioussis

  • Department of Physics, California State University, Northridge, California 91330-8268

S. G. Demos and H. B. Radousky

  • Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94580

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Issue

Vol. 65, Iss. 2 — 1 January 2002

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