Confinement-Induced Isosymmetric Metal-Insulator Transition in Ultrathin Epitaxial V₂O₃ Films

Area of Science:

• Materials Science
• Condensed Matter Physics
• Oxide Electronics

Background:

• Dimensional confinement is crucial for tuning properties in complex oxides.
• Understanding electron correlations in reduced dimensions is key for novel electronic devices.

Purpose of the Study:

• To achieve atomic-layered growth of trigonal vanadium sesquioxide (V2O3) films.
• To investigate the effects of dimensional confinement on electron correlations and phase transitions.
• To explore the role of confinement-induced stress in correlated oxides.

Main Methods:

• Oxygen-assisted molecular beam epitaxy for atomic-layered growth.
• Electrical and optical measurements to detect phase transitions.
• Photoemission spectroscopy to probe electronic structure and quasiparticle weight.

Main Results:

• High-quality epitaxial ultrathin V2O3 films down to unit cell thickness were fabricated.
• A dimensional confinement-induced metal-insulator transition was observed.
• The transition was identified as Mott-Hubbard, with vanishing quasiparticle weight.
• Dimensional confinement was shown to induce effective out-of-plane stress.

Conclusions:

• Dimensional confinement provides a pathway to tune the electronic properties of V2O3.
• Confinement-induced stress plays a significant role in the behavior of correlated oxides.
• This work offers a method to control lattice components via strain and confinement for oxide electronics.