Dimensionality-Driven Metal-Insulator Transition in Spin-Orbit-Coupled SrIrO_{3}

Area of Science:

• Condensed matter physics
• Materials science
• Solid-state chemistry

Background:

• Epitaxially stabilized strontium iridate (SrIrO3) ultrathin films exhibit complex electronic properties.
• Spin-orbit coupling significantly influences the electronic behavior of iridates.

Purpose of the Study:

• Investigate the metal-insulator transition in SrIrO3 ultrathin films upon reduction of film thickness.
• Identify the microscopic mechanisms driving this transition.
• Explore potential pathways towards unconventional superconductivity.

Main Methods:

• Epitaxial stabilization of SrIrO3 ultrathin films.
• Experimental measurement of electronic dispersions.
• Density functional theory (DFT) calculations at various complexity levels.

Main Results:

• Observed a metal-insulator transition in SrIrO3 ultrathin films as thickness was reduced.
• Identified dimensionality-induced readjustments in octahedral rotations, magnetism, and electronic correlations as key mechanisms.
• Found a striking resemblance between the 2D limit band structure of SrIrO3 and bulk Sr2IrO4.

Conclusions:

• The metal-insulator transition in SrIrO3 ultrathin films is driven by dimensionality effects.
• The observed band structure similarity opens possibilities for achieving unconventional superconductivity.
• Electric field gating offers a route for "clean" electron doping to induce superconductivity.