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| Main Authors: | , , , |
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| Format: | Preprint |
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2026
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| Subjects: | |
| Online Access: | https://arxiv.org/abs/2601.15438 |
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| _version_ | 1866915746430320640 |
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| author | Prakash, Viswesh Tang, Jingyu Porter, Lisa M. Kurchin, Rachel C. |
| author_facet | Prakash, Viswesh Tang, Jingyu Porter, Lisa M. Kurchin, Rachel C. |
| contents | In this study, we investigate the effect of Mg incorporation on the relative phase stability of the four primary Ga$_2$O$_3$ polymorphs using density functional theory (DFT) calculations, with the goal of rationalizing experimental observations suggesting that diffusion from MgAl$_2$O$_4$ substrates contributes to relative stabilization of the $γ$ phase. Mg incorporation is modeled up to 25% of Ga sites within supercells derived from fully relaxed unit cells of each polymorph. Our results show that while $β$-Ga$_2$O$_3$ remains the thermodynamically most stable phase, the enthalpic differences between polymorphs decrease with increasing Mg content. The inherently disordered $γ$ phase, with its high configurational entropy, becomes less energetically unfavorable under Mg substitution, suggesting that entropy-driven stabilization may facilitate its formation under high-temperature and/or nonequilibrium growth conditions such as those previously reported. These findings provide a thermodynamic rationale for the experimental observation of the $γ$ phase during epitaxial growth on MgAl$_2$O$_4$ spinel substrates. |
| format | Preprint |
| id |
arxiv_https___arxiv_org_abs_2601_15438 |
| institution | arXiv |
| publishDate | 2026 |
| record_format | arxiv |
| spellingShingle | First-Principles Study of Mg-Induced Phase Stabilization in Ga$_2$O$_3$ polymorphs Prakash, Viswesh Tang, Jingyu Porter, Lisa M. Kurchin, Rachel C. Materials Science In this study, we investigate the effect of Mg incorporation on the relative phase stability of the four primary Ga$_2$O$_3$ polymorphs using density functional theory (DFT) calculations, with the goal of rationalizing experimental observations suggesting that diffusion from MgAl$_2$O$_4$ substrates contributes to relative stabilization of the $γ$ phase. Mg incorporation is modeled up to 25% of Ga sites within supercells derived from fully relaxed unit cells of each polymorph. Our results show that while $β$-Ga$_2$O$_3$ remains the thermodynamically most stable phase, the enthalpic differences between polymorphs decrease with increasing Mg content. The inherently disordered $γ$ phase, with its high configurational entropy, becomes less energetically unfavorable under Mg substitution, suggesting that entropy-driven stabilization may facilitate its formation under high-temperature and/or nonequilibrium growth conditions such as those previously reported. These findings provide a thermodynamic rationale for the experimental observation of the $γ$ phase during epitaxial growth on MgAl$_2$O$_4$ spinel substrates. |
| title | First-Principles Study of Mg-Induced Phase Stabilization in Ga$_2$O$_3$ polymorphs |
| topic | Materials Science |
| url | https://arxiv.org/abs/2601.15438 |