A two-dimensional multiferroic metal with voltage-tunable magnetization and metallicity

Area of Science:

• Condensed Matter Physics
• Materials Science
• Solid-State Chemistry

Background:

• Multiferroic materials exhibit simultaneous ferroic orders, such as ferromagnetism and ferroelectricity.
• Achieving multiferroicity in two-dimensional (2D) materials, especially metals, presents significant challenges.
• Existing 2D multiferroics often lack metallic properties or require transition metals.

Purpose of the Study:

• To design and demonstrate a novel 2D multiferroic metal.
• To achieve simultaneous ferromagnetism, ferroelectricity, and metallicity in a single material.
• To explore electrical switching of magnetic and metallic properties in 2D materials.

Main Methods:

• Utilizing first-principles calculations to investigate material properties.
• Employing hole doping and arsenic doping strategies on monolayer α-In2Se3.
• Analyzing the effects of out-of-plane polarization and strain engineering.

Main Results:

• Demonstrated a strong magnetoelectric effect in hole-doped and arsenic-doped monolayer α-In2Se3.
• Showcased electrical switching of 2D magnetization and metallicity via asymmetric doping.
• Observed electric field-tunable charge disproportionation and switching of local magnetic moments in arsenic defect pairs.

Conclusions:

• A design principle for non-transition metal 2D multiferroic metals was established.
• Asymmetric doping and strain engineering offer pathways for controlling multiferroic properties.
• The findings expand the material design space for advanced 2D electronic and spintronic devices.