Single-Layer Tl₂O: A Metal-Shrouded 2D Semiconductor with High Electronic Mobility.

Area of Science:

• Materials Science
• Condensed Matter Physics
• Solid State Chemistry

Background:

• Two-dimensional (2D) materials are revolutionizing electronics.
• Metal-shrouded 2D semiconductors offer unique electronic and interfacial properties.
• Thallium Oxide (Tl2O) has not been previously explored as a 2D semiconductor.

Purpose of the Study:

• To investigate the fundamental properties of single-layer Tl2O.
• To assess its stability, electronic band structure, and charge carrier mobility.
• To explore its potential for 2D electronic applications.

Main Methods:

• First-principles calculations were employed.
• Thermal and dynamic stability were evaluated.
• Electronic band structure and charge carrier mobility were computed.

Main Results:

• Single-layer Tl2O is thermally and dynamically stable.
• It possesses a direct bandgap of 1.56 eV and high charge carrier mobility (4.3 × 10^3 cm^2 V^-1 s^-1).
• A layer-thickness-dependent direct-to-indirect bandgap transition was observed; bulk Tl2O is also semiconducting.

Conclusions:

• Single-layer Tl2O is a promising metal-shrouded 2D semiconductor.
• Its stability and excellent electronic properties suggest significant potential in 2D electronics.
• The findings challenge previous literature regarding the semiconducting nature of bulk Tl2O.