Abstract
MnNiO3 is a strongly correlated transition metal oxide that has recently been investigated theoretically for its potential application as an oxygen-evolution photocatalyst. However, there is no experimental report on critical quantities such as the band gap or bulk modulus. Recent theoretical predictions with standard functionals such as LDA+U and HSE show large discrepancies in the band gaps (about 1.23 eV), depending on the nature of the functional used. Hence there is clearly a need for an accurate quantitative prediction of the band gap to gauge its utility as a photocatalyst. In this work, we present a diffusion quantum Monte Carlo study of the bulk properties of MnNiO3 and revisit the synthesis and experimental properties of the compound. We predict quasiparticle band gaps of 2.0(5) eV and 3.8(6) eV for the majority and minority spin channels, respectively, and an equilibrium volume of 92.8 Å3, which compares well to the experimental value of 94.4 Å3. A bulk modulus of 217 GPa is predicted for MnNiO3. We rationalize the difficulty for the formation of ordered ilmenite-type structure with specific sites for Ni and Mn to be potentially due to the formation of antisite defects that form during synthesis, which ultimately affects the physical properties of MnNiO3.
Original language | English |
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Article number | 174703 |
Journal | Journal of Chemical Physics |
Volume | 147 |
Issue number | 17 |
DOIs | |
State | Published - Nov 7 2017 |
Funding
The authors are grateful to Michael McGuire for helpful discussions. This work was supported by the Materials Science and Engineering Division of the U.S. Department of Energy Office of Science (BES). This research used resources of the Oak Ridge Leadership Computing Facility at the Oak Ridge National Lab, which is supported by the Office of Science of the U.S. Department of Energy under Contract No. DE-AC05-00OR22725.
Funders | Funder number |
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Materials Science and Engineering Division | |
U.S. Department of Energy Office of Science | |
U.S. Department of Energy | |
Office of Science | |
Basic Energy Sciences |