Possible Orthorhombic Phase of Ta₂O₅ under High Pressures

2025/07/19 by Gong, Yan, Tang, HuiMin, Yang, Yong +1
#FOS: Physical sciences #Materials Science (cond-mat.mtrl-sci)

paper · doi:10.48550/arxiv.2507.14514

Abstract

A potential orthorhombic phase of Ta₂O₅, designated as Y-Ta₂O₅, is predicted under high-pressure conditions through density functional theory (DFT) calculations combined with structural search algorithms. This phase, consisting of four formula units per unit cell (Z = 4), exhibits the highest known Ta-O coordination numbers. Y-Ta₂O₅ is found to be the most energetically favorable form of Ta₂O₅ in the pressure range of approximately 70 GPa to at least 200 GPa. Both standard DFT-GGA and higher-accuracy GW calculations reveal that Y-Ta₂O₅ is a wide bandgap semiconductor with a direct bandgap. Additionally, nuclear quantum effects (NQEs) introduce nontrivial corrections to external pressure at fixed volumes, underscoring their significance in high-pressure phase stability analyses.

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