Materials Theory, abstract
mtrl-th/9509005
From: David Vanderbilt <dhv@physics.rutgers.edu>
Date: Thu, 21 Sep 1995 14:42:56 -0400
Effect of quantum fluctuations on structural phase transitions in SrTiO_3 and BaTiO_3
Authors: W. Zhong , David Vanderbilt
(Department of Physics and Astronomy, Rutgers University)
Comments: Revtex (preprint style, 14 pages) + 2 postscript figures. A version
in two-column article style with embedded figures is available at
this http URL
Using path-integral Monte Carol simulations and an ab initio effective
Hamiltonian, we study the effects of quantum fluctuations on structural phase
transitions in the cubic perovskite compounds SrTiO3 and BaTiO3. We find
quantum fluctuations affect ferroelectric (FE) transitions more strongly than
antiferrodistortive (AFD) ones, even though the effective mass of a single FE
local mode is larger. For SrTiO3 we find that the quantum fluctuations suppress
the FE transition completely, and reduce the AFD transition temperature from
130K to 110K. For BaTiO3, quantum fluctuations do not affect the order of the
transition, but do reduce the transition temperature by 35-50 K. The
implications of the calculations are discussed.
(N.B.: delivery types and potential problems)
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