Improved electronic structure and magnetic exchange interactions in transition metal oxides

Area of Science:

• Condensed Matter Physics
• Materials Science
• Computational Chemistry

Background:

• Traditional density functional theory (DFT)+U and hybrid functionals face challenges in accurately and efficiently describing strongly correlated transition metal oxides.
• Accurate electronic structure calculations are crucial for understanding and designing materials with specific properties.

Purpose of the Study:

• To evaluate the Agapito Curtarolo and Buongiorno Nardelli (ACBN0) pseudo-hybrid Hubbard density functional for transition metal oxides.
• To assess ACBN0 as a computationally efficient and accurate alternative to existing methods.

Main Methods:

• Application of the ACBN0 functional to simple binary transition metal oxides (MnO, CoO, NiO, FeO) and mixed valence compounds (Co3O4, Mn3O4).
• Calculation of Hubbard energy within ACBN0 through direct evaluation of local Coulomb and exchange integrals with density matrix renormalization for screening.
• Comparison of ACBN0 results with DFT+U, hybrid functionals, GW approximation, and experimental data.

Main Results:

• ACBN0 provides a fast, reasonably accurate, and parameter-free approach for simple binary metal oxides.
• The method successfully predicts electronic properties of mono-oxides (MnO, CoO, NiO, FeO) at equilibrium and under pressure.
• Results for binary and mixed valence oxides show excellent agreement with advanced computational methods and experimental measurements.

Conclusions:

• ACBN0 is a viable and efficient alternative to traditional DFT+U and hybrid methods for transition metal oxides.
• The ACBN0 functional offers a computationally inexpensive yet accurate route to study the electronic properties of these materials.
• This work validates ACBN0 for a range of technologically relevant transition metal oxides.