Ni(NCS)₂ monolayer: a robust bipolar magnetic semiconductor

Area of Science:

• Materials Science
• Condensed Matter Physics
• Solid State Chemistry

Background:

• The search for intrinsic two-dimensional (2D) ferromagnetic semiconductors is crucial for developing nanoscale spintronic devices.
• Existing 2D magnetic materials often face challenges with stability, synthesis, or operating temperatures.

Purpose of the Study:

• To investigate the electronic and magnetic properties of the Ni(NCS)₂ monolayer using first-principles calculations.
• To assess the stability and potential for exfoliation of the Ni(NCS)₂ monolayer.
• To explore the effects of strain and doping on the magnetic ordering of Ni(NCS)₂.

Main Methods:

• First-principles calculations (e.g., density functional theory).
• Monte Carlo simulations for Curie temperature estimation.
• Phonon spectrum, ab initio molecular dynamics, and elastic constant calculations for stability assessment.

Main Results:

• Ni(NCS)₂ monolayer identified as a robust bipolar ferromagnetic semiconductor with a bandgap of ~1.5 eV.
• Calculated Curie temperature of approximately 37 K.
• Ferromagnetic ordering is maintained under strain and electron doping, but transitions to antiferromagnetic with high hole doping.
• Small exfoliation energy suggests potential for isolation from bulk.
• Thermodynamic, dynamic, and mechanical stability confirmed.

Conclusions:

• The Ni(NCS)₂ monolayer is a promising candidate for a novel 2D ferromagnetic material within magnetic molecular frameworks.
• Its stability and tunable magnetic properties make it suitable for potential applications in magnetic nanoelectronic devices.