The atomic order, electronic structure and thermodynamic stability of nickel aluminate, NiAl2O4, have been analyzed using periodic density functional theory and cluster expansion. NiAl2O4 forms a tetragonal structure with P4122 space group. At temperatures below 800 K, it is an inverse spinel, with Ni occupying the octahedral sites and Al occupying both the octahedral and the tetrahedral sites. Some Niocta + Altetra ⇌ Nitetra + Alocta exchange occurs above 800 K, but the structure remains largely inverse at high temperatures, with about 95% Niocta at 1500 K. Various functionals, with and without van der Waals corrections, were used to predict the experimental formation energy, lattice parameters and electronic structure. In all cases, the NiAl2O4 is found to be ferromagnetic and a semiconductor with an indirect band gap along the Γ → M symmetry points.
|Number of pages||10|
|Journal||Physical Chemistry Chemical Physics|
|Publication status||Published - 2019|
Bibliographical noteFunding Information:
I. E., A. S. and A. M. gratefully acknowledge the fund provided by the University of Sydney – Yonsei Joint Research Funding Scheme, International Program Development Fund. I. E. and A. M. also gratefully acknowledge the computational resources provided by Artemis HPC system at the University of Sydney and by Intersect with the assistance of the Australian National Computational Infrastructure (NCI).
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All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry