2014/01/22 by A. Beltrán, Lourdes Gracia, E. Longo +1 · 1 citation
Materials Science · Physics and Astronomy · Engineering · Chemistry · #Heusler alloys: electronic and magnetic properties #Advanced Condensed Matter Physics #Gas Sensing Nanomaterials and Sensors #Tetragonal crystal system #Orthorhombic crystal system #Spinel #Phase diagram #Electronic structure #Electronic band structure #Density functional theory #Density of states #Local-density approximation #Materials science #Condensed matter physics #Chemistry #Thermodynamics #Crystal structure #Phase (matter) #Crystallography #Computational chemistry #Physics #Metallurgy
paper · doi:10.1021/jp4118024
openalex publication_date 2014/01/22 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/02
We have performed a systematic first-principles investigation by using the density functional formalism with the nonlocal B3LYP approximation to calculate structural and electronic properties as well as phase transitions under pressure of silver molybdate, Ag 2 MoO 4 . Five phases have been considered: tetragonal Ag 2 MoO 4 (with normal and inverse P 4 1 22 structures), β-Ag 2 MoO 4 (cubic spinel structure), olivine-type (orthorhombic structure), and α-Ag 2 MoO 4 (tetragonal K 2 NiF 4 -type structure). Numerical and analytical fittings have been conducted to determine the equilibrium unit cell geometry and equation-of-state parameters for all structures and compounds involved in the phase diagram. Pressure dependencies of band structures, energy gaps, density-of-states (DOS), and vibrational frequencies were investigated. Theoretical results show that the inverse Ag 2 MoO 4 with P 4 1 22 symmetry is more stable above 15 GPa than the normal spinel structure, while the tetragonal structure is slightly more stable than the cubic representation above 6 GPa due to a tetragonal distortion. We determined the stability against decomposition of Ag 2 MoO 4 toward binary oxides (MoO 2, MoO 3, Ag 2 O, AgO, and Ag 2 O 3 ), metal (Ag and Mo), oxygen, and Ag 2 Mo 2 O 7 . Theoretical results point out that β-Ag 2 MoO 4 can decompose into Ag 2 Mo 2 O 7 and Ag 2 O at 12 GPa.