Exploration of Stable Strontium Phosphide-Based Electrides: Theoretical Structure Prediction and Experimental...

Area of Science:

• Materials Science
• Solid State Physics
• Computational Chemistry

Background:

• Alkaline-earth-metal-based electrides like C12A7:e- and [Ca2N]+:e- have been successfully synthesized.
• High-throughput database screening has accelerated the discovery of new materials.

Purpose of the Study:

• To explore the potential for new electrides in the strontium-phosphorus (Sr-P) system.
• To combine theoretical predictions with experimental validation for novel electride discovery.

Main Methods:

• Ab initio evolutionary structure searches were employed to predict new strontium phosphide structures.
• First-principles calculations were used to analyze the electronic properties of predicted structures.
• Experimental synthesis and structural confirmation of Sr5P3 were performed.

Main Results:

• New strontium phosphide structures (Sr5P3, Sr8P5, Sr3P2, Sr4P3) were theoretically predicted.
• Sr5P3 and Sr8P5 were identified as potential electrides with quasi-one-dimensional (1D) and zero-dimensional (0D) character, respectively.
• The synthesis of Sr5P3 was achieved, and its structure was experimentally confirmed, revealing semiconducting properties contrary to initial metallic predictions.

Conclusions:

• Sr5P3 is a novel 1D electride with semiconducting behavior due to a distinct band gap and half-filled band by unpaired electrons.
• The semiconducting nature of Sr5P3 has significant implications for the general understanding of 1D electrides.
• A mechanism for electride formation, including an orbital level diagram, was proposed based on first-principles calculations.