Physics – Condensed Matter – Materials Science
Scientific paper
2011-10-05
Physics
Condensed Matter
Materials Science
Accepted for publication in Physical Review B
Scientific paper
We report total energy calculations for different crystal structures of NaNbO$_3$ over a range of unit cell volumes using the all-electron full-potential (L)APW method. We employed both the local-density approximation (LDA) and the Wu-Cohen form of the generalized gradient approximation (GGA-WC) to test the accuracy of these functionals for the description of the complex structural behavior of NaNbO$_3$. We found that LDA not only underestimates the equilibrium volume of the system but also predicts an incorrect ground state for this oxide. The GGA-WC functional, on the other hand, significantly improves the equilibrium volume and provides relative phase stability in better agreement with experiments. We then use the GGA-WC functional for the calculation of the phonon dispersion curves of cubic NaNbO$_3$ to identify the presence of structural instabilities in the whole Brillouin zone. Finally, we report comparative calculations of structural instabilities as a function of volume in NaNbO$_3$ and KNbO$_3$ to provide insights for the understanding of the structural behavior of K$_{1-x}$Na$_x$NbO$_3$ solid solutions.
Machado Raphael
Sepliarsky M.
Stachiotti M. G.
No associations
LandOfFree
Relative phase stability and lattice dynamics of NaNbO$_3$ from first-principles calculations 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 Relative phase stability and lattice dynamics of NaNbO$_3$ from first-principles calculations, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Relative phase stability and lattice dynamics of NaNbO$_3$ from first-principles calculations will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-325847