Volume 105, Number 4, February 2014
|Number of page(s)||6|
|Section||Condensed Matter: Structural, Mechanical and Thermal Properties|
|Published online||25 February 2014|
New high-pressure phase of MgH2: An ab initio constant-pressure study
Department of Physics, Texas Tech University - Lubbock, TX, 79409, USA and Department of Advanced Materials and Nanotechnology, Abdullah Gül University - Kayseri, 38039, Turkey
Received: 29 November 2013
Accepted: 5 February 2014
The stability of magnesium hydride (MgH2) at high pressure is studied using a constant-pressure ab initio technique. Two phase transformations are successfully observed through the simulations. The rutile structure undergoes a phase transformation into a CaCl2-type phase. Further increase in pressure results into a first-order phase transition into an orthorhombic state within Pbcm symmetry. This phase can be considered as a distorted CaF2-type crystal and does not correspond to the previously proposed MgH2 phases. The transformation mechanism of the CaCl2-Pbcm phase change at the atomistic level is successfully characterized and it is found that the CaCl2-to-Pbcm phase change proceeds via an ideal CaF2-type intermediate phase. These phase transformations are also analyzed using total energy-volume calculations.
PACS: 64.70.K- – Solid-solid transitions / 61.50.Ks – Crystallographic aspects of phase transformations; pressure effects
© EPLA, 2014
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.