Near-zero Poisson's ratio monolayer bismuthene

Area of Science:

• Materials Science
• Condensed Matter Physics
• Computational Materials Science

Background:

• Two-dimensional (2D) materials offer unique properties for advanced applications.
• Mechanical and electronic properties of 2D materials are crucial for device design.
• Bismuthene is an emerging 2D material with potential for novel functionalities.

Purpose of the Study:

• To investigate the mechanical and electronic properties of monolayer P2/m bismuthene using first-principles calculations.
• To explore the effects of uniaxial strain on the material's anisotropy and band gap.
• To assess the potential of P2/m bismuthene for flexible optoelectronic applications.

Main Methods:

• First-principles density functional theory (DFT) calculations.
• Simulation of uniaxial strain along armchair (X) and zigzag (Y) directions.
• Analysis of mechanical anisotropy (Poisson's ratio) and electronic band structure.

Main Results:

• Monolayer P2/m bismuthene displays significant mechanical anisotropy with distinct Poisson's ratios (0.737 for X, 0.056 for Y).
• Uniaxial strain tunes the electronic band gap from 0.12 to 0.39 eV.
• A reversible, strain-induced transition from indirect- to direct-band-gap semiconductor is observed.

Conclusions:

• P2/m bismuthene is a rare 2D material with coupled anisotropic mechanical and tunable electronic properties.
• Its unique characteristics make it a promising candidate for flexible optoelectronic devices.
• Theoretical insights guide future experimental synthesis and application of P2/m bismuthene.