Thickness Dependent Magnetic Transition in Few Layer 1T Phase CrTe₂

Area of Science:

• Condensed Matter Physics
• Materials Science
• Nanotechnology

Background:

• Room temperature two-dimensional (2D) ferromagnetism is crucial for spintronics.
• Synthesized 1T-CrTe2 nanosheets (5+ layers) show ferromagnetic properties near 305 K.
• The magnetic behavior of ultrathin CrTe2, down to the monolayer limit, is not well understood.

Purpose of the Study:

• To investigate the thickness-dependent magnetic properties of 1T-CrTe2 nanosheets.
• To explore the magnetic phase transitions from monolayer to thicker layers.
• To understand the fundamental mechanisms governing magnetism in few-layer CrTe2.

Main Methods:

• First-principles calculations were employed to simulate CrTe2 nanosheets.
• The study focused on layers ranging from 1 to 6.
• Magnetic coupling (ferromagnetic and antiferromagnetic) was analyzed for different thicknesses.

Main Results:

• Monolayer CrTe2 unexpectedly favors a zigzag antiferromagnetic (AFM) state.
• CrTe2 layers from 2 to 4 exhibit both intralayer and interlayer AFM coupling.
• CrTe2 nanosheets with 5 or more layers display ferromagnetic (FM) intralayer and interlayer coupling.

Conclusions:

• The magnetic properties of 1T-CrTe2 are highly dependent on the number of layers.
• Ferromagnetism is observed in thicker CrTe2 (≥5 layers), while thinner layers are antiferromagnetic.
• This thickness-dependent magnetism offers novel strategies for controlling magnetic behavior in 2D materials for spintronic applications.