Stability predictions of magnetic M₂AX compounds

Area of Science:

• Materials Science
• Computational Materials Science
• Solid-State Chemistry

Background:

• M₂AX compounds are a class of materials with potential applications in various fields.
• Systematic evaluation of their stability is crucial for predicting and guiding synthesis efforts.
• Previous studies have synthesized some M₂AX compounds, but a comprehensive stability analysis is lacking.

Purpose of the Study:

• To systematically assess the thermodynamic, mechanical, and dynamical stability of 580 M₂AX compounds.
• To identify novel stable M₂AX compounds using high-throughput density functional theory calculations.
• To understand stability trends concerning M and A elements and analyze magnetic structures.

Main Methods:

• High-throughput density functional theory (DFT) calculations were employed.
• Evaluated thermodynamic, mechanical, and dynamical stability criteria.
• Analyzed formation energies and crystal orbital Hamilton population (COHP) for stability insights.

Main Results:

• Identified 20 M₂AX compounds that satisfy all three stability criteria.
• Confirmed the stability of previously synthesized compounds such as Cr₂AlC, Cr₂GeC, Cr₂GaC, Cr₂GaN, and Mn₂GaC.
• Found that Cr- and Mn-based M₂AX compounds exhibit greater stability compared to Fe, Co, or Ni analogs.

Conclusions:

• The study provides a comprehensive stability assessment of a large M₂AX compound dataset.
• Cr and Mn are identified as favorable elements for designing stable M₂AX materials.
• The findings guide the search for new stable M₂AX compounds with potential technological applications.