First-Principles and PSO-Driven Exploration of Ca-Pt Intermetallics: Stable Phases and Pressure-Driven Transitions

In this study, first-principles calculations in conjunction with the particle swarm optimization (PSO) algorithm structure search method were employed to investigate the stable phases of Ca-Pt intermetallic compounds under various pressure conditions. The previously reported CaPt<sub>5</sub...

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Bibliographic Details
Main Authors: Yifei Wang, Dengjie Yan
Format: Article
Language:English
Published: MDPI AG 2025-03-01
Series:Crystals
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Online Access:https://www.mdpi.com/2073-4352/15/3/263
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Summary:In this study, first-principles calculations in conjunction with the particle swarm optimization (PSO) algorithm structure search method were employed to investigate the stable phases of Ca-Pt intermetallic compounds under various pressure conditions. The previously reported CaPt<sub>5</sub> phase and the hitherto unreported phases Ca<sub>3</sub>Pt and Ca<sub>2</sub>Pt were successfully predicted, perfecting the known phase diagram for Ca-Pt intermetallic compounds. Furthermore, the pressure-induced phase transition in Ca<sub>2</sub>Pt has been identified. The structure of Ca<sub>2</sub>Pt undergoes a phase transition from Cmmm to C2/m and then to Cm at pressures ranging from 25 to 75 GPa. Electronic properties analyses revealed stable metallic bonds between the Ca and Pt atoms in the Ca-Pt intermetallic compounds. Simultaneously, the anionic character of the Pt atoms and the localization of electrons within the intermetallic compounds were observed. Analysis of the mechanical properties showed that Ca<sub>3</sub>Pt and CaPt<sub>5</sub> exhibited different degrees of anisotropy. The CaPt<sub>5</sub> structure exhibits significant transverse isotropy, whereas the Ca<sub>3</sub>Pt structure exhibits pronounced anisotropic behavior. The results of this study provide theoretical support for further research on Ca-Pt intermetallic compounds and the expansion of Pt oxidation states.
ISSN:2073-4352