Physics – Condensed Matter – Materials Science
Scientific paper
2002-03-14
AIP Conf. Proc. -- August 17, 2002 -- Volume 626, pp. 56-63 Fundamental Physics Of Ferroelectrics 2002
Physics
Condensed Matter
Materials Science
5 pages, with 2 postscript figures embedded. Proceedings of "Fundamental Physics of Ferroelectrics, 2002", R. Cohen and T. Ega
Scientific paper
10.1063/1.1499552
The phase-transition sequence of a ferroelectric perovskite such as BaTiO_3 can be simulated by computing the statistical mechanics of a first-principles derived effective Hamiltonian [Zhong, Vanderbilt and Rabe, Phys. Rev. Lett. 73, 1861 (1994)]. Within this method, the effect of an external pressure (in general, of any external field) can be studied by considering the appropriate "enthalpy" instead of the effective Hamiltonian itself. The legitimacy of this approach relies on two critical assumptions that, to the best of our knowledge, have not been adequately discussed in the literature to date: (i) that the zero-pressure relevant degrees of freedom are still the only relevant degrees of freedom at finite pressures, and (ii) that the truncation of the Taylor expansion of the energy considered in the effective Hamiltonian remains a good approximation at finite pressures. Here we address these issues in detail and present illustrative first-principles results for BaTiO_3. We also discuss how to construct effective Hamiltonians in cases in which these assumptions do not hold.
Íñiguez Jorge
Neaton Jeffrey B.
Vanderbilt David
No associations
LandOfFree
Effective-Hamiltonian modeling of external pressures in ferroelectric perovskites does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Effective-Hamiltonian modeling of external pressures in ferroelectric perovskites, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Effective-Hamiltonian modeling of external pressures in ferroelectric perovskites will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-9230