Intrinsic Ferroelectric Quantum Spin Hall Insulator in Monolayer Na₃Bi with Surface Trimerization

Area of Science:

• Materials Science
• Condensed Matter Physics
• Quantum Chemistry

Background:

• Two-dimensional (2D) ferroelectric quantum spin Hall (FEQSH) insulators are typically engineered, hindering practical applications.
• Discovering intrinsic FEQSH materials is crucial for next-generation nonvolatile electronics.

Purpose of the Study:

• To identify and characterize an intrinsic 2D FEQSH insulator.
• To explore the potential of novel 2D materials for advanced electronic devices.

Main Methods:

• First-principles calculations were employed to investigate material properties.
• The study focused on monolayer Na3Bi with surface trimerization.

Main Results:

• Monolayer Na3Bi was identified as an intrinsic 2D FEQSH insulator.
• The material exhibits large ferroelectric polarization, a significant band gap, and a low switching barrier.
• Nonvolatile switching of spin textures is achievable through inherent ferroelectricity.

Conclusions:

• Monolayer Na3Bi presents a unique combination of ferroelectric and topological phases.
• This intrinsic 2D FEQSH insulator serves as a promising platform for scientific discovery and technological innovation.