αh-GeSe: a multifunctional semiconductor combining auxeticity and piezoelectricity

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Multifunctional materials are crucial for next-generation nanodevices.
• Designing materials with combined properties like auxeticity and piezoelectricity is challenging.

Purpose of the Study:

• To design and investigate novel two-dimensional (2D) materials with combined auxetic and piezoelectric properties.
• To explore the potential of monolayer αh-GeSe for nanodevice applications.

Main Methods:

• First principles calculations were employed to design and analyze the materials.
• Mechanical stability was confirmed using elastic constants and phonon dispersion curves.

Main Results:

• Monolayer αh-GeSe exhibits in-plane auxeticity (negative Poisson's ratio) along the diagonal direction.
• An out-of-plane negative Poisson's ratio was observed under tensile strain in the x-direction.
• The material demonstrates strong anisotropic in-plane piezoelectric properties due to broken central symmetry.

Conclusions:

• Monolayer αh-GeSe is a mechanically and dynamically stable multifunctional material.
• Its unique combination of in-plane and out-of-plane auxeticity, along with piezoelectricity, makes it a promising candidate for advanced nanodevices.