Premium
A systematic first‐principles study of the tungsten trioxide polymorphs
Author(s) -
AlvarezQuiceno Juan C.,
Dalpian Gustavo M.,
OsorioGuillén Jorge M.
Publication year - 2015
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.201552270
Subject(s) - phase diagram , tungsten trioxide , density functional theory , thermodynamics , ab initio , materials science , valence (chemistry) , hybrid functional , phase transition , tungsten , band gap , phase (matter) , crystallography , chemistry , computational chemistry , physics , organic chemistry , optoelectronics , metallurgy
Tungsten trioxide (WO3 ) is a compound that has a high degree of polymorphism, but a detailed phase diagram of this material is not available in the literature and a systematic ab‐initio study including all its crystallographic phases does not exist. In this work, we have performed a first‐principles density functional theory study of all WO3 crystalline phases within the generalized gradient and hybrid approximations of the exchange–correlation functional. We have calculated the equations of state, the isothermal bulk moduli, the Γ ‐centered vibrational frequencies, and the phase diagram using the Debye–Einstein model. The calculated phase diagram shows only the γ → ϵ crystallographic phase transition at high pressure and low temperature, being the γ ‐phase the stable polymorph at room temperature and ambient pressure, and the ϵ ‐phase stable at low temperatures and high pressures. In addition, the band structures were calculated observing a variation of the energy gap between 1.76 up to 2.79 eV with a similar topology of the top valence and bottom conduction bands across all the polymorphs.