Metal-Insulator Transition in VO_{2}: A DFT+DMFT Perspective

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Chemistry

Background:

• Vanadium dioxide (VO_{2}) exhibits a metal-insulator transition.
• Understanding the electronic structure of VO_{2} phases is key to its applications.

Purpose of the Study:

• Investigate the electronic structure of rutile (metallic) and monoclinic (insulating) VO_{2} phases.
• Elucidate the mechanism of gap opening in insulating VO_{2} phases.
• Explore the role of Mott physics in VO_{2} electronic properties.

Main Methods:

• Fully self-consistent density functional theory (DFT) combined with embedded dynamical mean-field theory (DMFT).
• Theoretical investigation of electronic structure and correlations.

Main Results:

• Mott physics is essential across all VO_{2} phases.
• A distinct mechanism for gap opening is proposed, involving local moment formation and strong intersite correlations.
• The rutile to M_{1} phase transition is a Mott transition influenced by intersite exchange.
• The electronic temperature dependence of the gap in the M_{1} phase is demonstrated.

Conclusions:

• Mott physics governs the electronic behavior of VO_{2}.
• The proposed mechanism provides a unified understanding of VO_{2} phases.
• The temperature-dependent gap in the M_{1} phase aligns with experimental observations.