Stability of the different AlOOH phases under pressure. (13th April 2016)

• Record Type: Journal Article
• Authors: Cedillo, Andrés; Torrent, Marc; Cortona, Pietro
• Is Part Of: Journal of physics. Volume 28:Number 18(2016)
• Publication Date: 2016-04-13
• Subjects: density functional theory -- exchange-correlation functionals -- aluminium hydroxides -- behaviour and phase transitions under pressure; Condensed matter -- Periodicals; Matière condensée -- Périodiques; Vaste stoffen; Vloeistoffen; Natuurkunde; Electronic journals; Computer network resources; 530.4105
• DOI: 10.1088/0953-8984/28/18/185401
• Languages: English
• ISSNs: 0953-8984

Abstract

Abstract: The pressure effects on three different AlOOH structures ( α, γ, and δ phases) are systematically analyzed by density functional theory with different exchange and correlation energy functional approximations, namely two local, two generalized-gradient approximation (GGA), and two GGA for solids (GGAsol). Phase stability, compressibility and hydrogen bond evolution are studied in a range of pressures from 0 to 30 GPa. In general, the use of GGAsol functionals is mandatory in order to have the correct phase stability order, a good description of the hydrogen bonds, and a close agreement with the experimental lattice parameters at the various pressures. Pressure-induced hydrogen-bond symmetrization is found in γ and δ phases at high compression, while the hydrogen bonds in the α phase remain asymmetric. A detailed analysis of the uncertainties on the values of the bulk moduli and their pressure derivative at zero pressure deduced by fitting calculated or experimental ( P, V ) data is also presented.