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Vacancy defects in MgO at high pressure
-
Bijaya B. Karki
and
Gaurav Khanduja
Published/Copyright:
March 31, 2015
Abstract
First-principles calculations within the local density and pseudopotential approximations were performed to investigate the effects of pressure on the energetics and structural behavior of charged vacancy defects in MgO. The simulations were performed for a supercell containing 216 atoms with their positions being fully optimized. In particular, the formation and migration energies of cation and anion vacancies were shown to substantially increase over the pressure regime of the Earth.s mantle. Our results thus suggest that pressure should suppress intrinsic diffusion mediated by ionic vacancies in MgO over the mantle pressure regime. The calculated three-dimensional data sets for atomic displacements and electron charge density were explored in detail using an interactive visualization system. Although the atomic and electronic structures are highly distorted in the close vicinity of the defects (i.e., in the region covering up to the nearest and next-nearest atoms), the effects are not negligible at farther distances
Keywords : Defects; mantle minerals; high pressure; rheology; first-principles calculations; scientific visualization
Received: 2004-11-19
Accepted: 2005-6-3
Published Online: 2015-3-31
Published in Print: 2006-4-1
© 2015 by Walter de Gruyter Berlin/Boston
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Keywords for this article
Defects;
mantle minerals;
high pressure;
rheology;
first-principles calculations;
scientific visualization
Articles in the same Issue
- Structural model for the biogenic Mn oxide produced by Pseudomonas putida
- Electron-beam (5–10 keV) damage in triplite-group phosphates: Consequences for electron-microprobe analysis of fluorine
- Vacancy defects in MgO at high pressure
- Plastic flow of pyrope at mantle pressure and temperature
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- Reinvestigation of the MgSiO3 perovskite structure at high pressure
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