Bimetal chalcogenide TM₂TM'X₄ monolayers: stable room temperature ferromagnetic semiconductors

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Two-dimensional (2D) ferromagnetic semiconductors (FMSs) are crucial for spintronics due to their combined magnetic and semiconducting properties.
• Developing stable 2D FMSs that operate at room temperature remains a significant challenge.

Purpose of the Study:

• To predict and characterize novel 2D FMS materials based on transition metal chalcogenides.
• To explore their electronic and magnetic properties, including stability and potential for spintronic applications.

Main Methods:

• First-principles calculations were employed to predict the properties of TM₂TM'X₄ monolayers.
• Density Functional Theory (DFT) was used to investigate electronic band structures, magnetic ordering, and stability under strain.

Main Results:

• A new class of stable 2D FMSs (TM₂TM'X₄) was predicted, including V₂NiTe₄, V₂TiTe₄, and Ti₂VSe₄.
• These materials exhibit tunable bandgaps (0.24-0.62 eV) and room-temperature magnetism with Curie temperatures up to 715 K.
• Ti₂VSe₄ and V₂NiTe₄ can be tuned into ferromagnetic half-metals under specific biaxial strains.

Conclusions:

• The predicted TM₂TM'X₄ monolayers are promising candidates for next-generation spintronic devices.
• Their electronic and magnetic properties can be effectively modulated by strain engineering.
• This work provides a theoretical foundation for designing novel 2D FMS materials.