A 2D ferromagnetic semiconductor in monolayer Cr-trihalide and its Janus structures

Area of Science:

• Materials Science
• Condensed Matter Physics
• Quantum Chemistry

Background:

• Two-dimensional (2D) materials offer unique electronic and magnetic properties.
• Chromium trihalides (CrX3) and their derivatives are promising candidates for spintronic applications.

Purpose of the Study:

• Investigate the physical properties of pristine and Janus chromium trihalide monolayers.
• Determine the stability, electronic band structure, magnetic properties, and optical characteristics of these 2D materials.

Main Methods:

• First principles calculations were employed to study material properties.
• Monte Carlo simulations were used to analyze magnetic behavior and Curie temperatures.

Main Results:

• Janus X3-Cr2-Y3 monolayers are dynamically stable and synthesizable.
• Both pristine and Janus CrX3 exhibit 2D ferromagnetic semiconducting band structures.
• Band gaps range up to 2.3 eV (Cl3-Cr2-Cl3), decreasing with heavier halides.
• Curie temperatures (Tc) strongly depend on halide composition.
• Janus structures possess dipole moments and dissimilar work functions, unlike non-polar pristine layers.
• Dielectric functions and refractive indices show weak frequency dependence; reflectivity is near zero.

Conclusions:

• Janus chromium trihalides are stable, tunable 2D ferromagnetic semiconductors.
• The halide composition critically influences electronic, magnetic, and optical properties.
• Asymmetric Janus structures offer potential for novel electronic and spintronic devices.