Computational design of axion insulators based on 5d spinel compounds

Area of Science:

• Materials Science
• Condensed Matter Physics
• Computational Materials Science

Background:

• Geometrically frustrated systems offer unique electronic and magnetic properties.
• Osmium oxides are potential candidates for novel quantum materials.

Purpose of the Study:

• To investigate the stability and electronic properties of osmium compounds in spinel structures.
• To explore the potential for large magnetoelectric coupling and exotic electronic phases.

Main Methods:

• Density functional theory (DFT) calculations.
• Local density approximation plus U (LDA+U) method.

Main Results:

• CaOs(2)O(4) and SrOs(2)O(4) can be stabilized in the spinel structure.
• Ferromagnetic order observed for relevant on-site Coulomb correlation (U) values.
• Large magnetoelectric coupling, characteristic of axion electrodynamics, predicted.
• Tunable electronic phases including 3D Weyl semimetal and Mott insulator identified.

Conclusions:

• Osmium-based spinels are promising materials for exploring complex electronic phenomena.
• The predicted magnetoelectric coupling suggests potential applications in advanced electronic devices.
• The tunability of electronic phases highlights the rich physics of these osmium compounds.