111-Type Semiconductor ReGaSi Follows 14e^- Rules.

Area of Science:

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

Background:

• Understanding the stability and properties of metal disilicides is crucial for materials design.
• Electron counting rules offer a predictive framework for novel intermetallic compounds.

Purpose of the Study:

• To apply electron counting rules to predict new stable ternary metal disilicides.
• To synthesize and characterize the predicted compound, ReGaSi.
• To elucidate the structural, electronic, and magnetic properties of ReGaSi.

Main Methods:

• Application of 14 established electron counting rules.
• Synthesis of the ternary phase ReGaSi.
• X-ray diffraction for structural determination.
• First-principles calculations (band structure, density of states, crystal orbital analysis).
• Experimental magnetic susceptibility measurements.

Main Results:

• Prediction and successful synthesis of the ordered semiconductor ReGaSi, a novel ternary phase.
• ReGaSi crystallizes in a primitive tetragonal structure (P4/nmm), related to MoSi₂-type ReSi₂, with ordered Ga and Si distribution.
• Calculations confirmed the electron count hypothesis and predicted a small indirect band gap of ~0.2 eV.
• First-principles calculations validated the observed site preference of Ga and Si.
• Experimental magnetic measurements confirmed the nonmagnetic nature of ReGaSi.

Conclusions:

• Electron counting rules are effective for predicting stable ternary metal disilicides.
• ReGaSi is a newly discovered stable ternary semiconductor with predictable electronic and magnetic properties.
• The study validates the synergy between theoretical prediction and experimental verification in materials discovery.