Strong Sliding Ferroelectricity and Interlayer Sliding Controllable Spintronic Effect in Two-Dimensional HgI₂ Layers

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• The development of two-dimensional (2D) materials for advanced electronic applications is a key research area.
• Sliding ferroelectric (FE) materials offer unique functionalities for next-generation devices, but experimental discovery remains challenging.
• The field of 2D "slidetronics" requires novel materials with detectable ferroelectricity and new functionalities.

Purpose of the Study:

• To identify and characterize new two-dimensional (2D) sliding ferroelectric materials.
• To explore the potential of these materials in 2D spintronic devices.
• To investigate the relationship between interlayer coupling, ferroelectricity, and spin texture.

Main Methods:

• First-principles calculations were employed to investigate van der Waals (vdW) layered crystals HgX2 (X = Br, I).
• Analysis of stacking sequences and interlayer coupling to determine ferroelectric properties.
• Simulation of electric field effects on ferroelectricity and spin texture.

Main Results:

• HgBr2 and HgI2 were identified as synthesizable 2D sliding ferroelectrics with stable out-of-plane ferroelectricity at room temperature.
• 2D HgI2 exhibits strong sliding ferroelectricity (up to 0.16 μC/cm²) due to strong interlayer coupling and interfacial charge rearrangement.
• Interlayer sliding in FE-HgI2 controls the Rashba spin texture, enabling potential spintronic applications.

Conclusions:

• HgX2 (X = Br, I) represent a new class of 2D sliding ferroelectric materials.
• The discovered materials demonstrate potential for practical applications in 2D slidetronics and spintronics.
• Electric control of electron spin detection is feasible in the 2D regime using FE-HgI2 layers.