Dimensionality-driven metal to Mott insulator transition in two-dimensional 1T-TaSe₂

Area of Science:

• Condensed matter physics
• Materials science
• Quantum phenomena

Background:

• Two-dimensional materials are key for studying quantum phenomena.
• Strongly correlated effects arise from electron-electron interactions in 2D.
• Reduced electron screening is the conventional explanation for these effects.

Purpose of the Study:

• Investigate the metal-to-Mott insulator transition in 1T-TaSe2.
• Determine the driving mechanism behind this transition.
• Understand the role of dimensionality in strongly correlated systems.

Main Methods:

• Experimental investigation of atomically thin 1T-TaSe2.
• Analysis of electronic band structure and kinetic energy.
• Comparison of bulk and thin-film properties.

Main Results:

• Discovered a metal-to-Mott insulator transition in 1T-TaSe2.
• Identified dimensionality crossover as the transition driver, challenging conventional screening theories.
• Found that reduced dimensionality quenches electron kinetic energy, inducing the Mott insulating state.

Conclusions:

• Dimensionality crossover, not screening, drives the metal-to-Mott insulator transition in 1T-TaSe2.
• This resolves the bulk metallic and surface insulating dichotomy in 1T-TaSe2.
• Opens new avenues for exploring strongly correlated systems by modulating material dimensionality.