Gallium oxide (Ga₂O₃) has attracted significant research interest for next‐generation high‐efficiency power devices because of its unique electronic properties such as ultra‐wide band gap, high breakdown electric field, and large Baliga’s figure of merit. Ga₂O₃ crystallizes in a series of reported polymorphs including β‐, α‐, ε‐, κ‐, γ‐, and δ‐Ga₂O₃, the structures of some of which are still in serious controversy. A polymorph structure search study of Ga₂O₃ is herein performed by combining particle swarm optimization with first‐principles energetic calculations. In addition to producing the predominant experimental known phases of β‐, α‐, and κ‐Ga₂O₃, two new polymorphs are found with space group P $\overline{1}$ and Pmc 2₁ consisting of four‐ and five‐fold coordinated Ga. They show comparable energy with β‐ and α‐Ga₂O₃ with the energy difference of several meV per atom, and exhibit robust phonon stability. Similarly, the new phases show quite wide band gaps and small electron effective masses by comparing it with other known phases. The Pmc 2₁ phase shows a calculated spontaneous polarization of 0.277 C m⁻², close to that of ε/κ‐Ga₂O₃. The systemic structure searches also establish a structural relationship between ε‐Ga₂O₃ and κ‐Ga₂O₃ and how the electronic properties vary with polymorphic phase change.

中文翻译：

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基于粒子群优化的结构搜索发现新的氧化镓多晶型物

氧化镓（Ga ₂ O ₃）由于其独特的电子特性（例如超宽带隙，高击穿电场和大Baliga品质因数）而吸引了下一代高效功率设备的大量研究兴趣。GA ₂ Ó ₃结晶的一系列报告多晶型物包括β-，α-，ε-，κ-，γ-，和δ-GA ₂ ö ₃，的其中一些的结构仍然严重争议。Ga ₂ O _3的多晶型结构搜索研究本文通过将粒子群优化与第一原理能量计算相结合来执行。除了产生的主要实验的相位已知β-，α-，和κ-镓₂ ö ₃，两个新的多晶型物发现，空间群P $\overline{\mathrm{1个}}$和PMC 2 ₁由四和五重配位Ga的，它们显示出相当的能量与β-和α-镓₂ ö ₃与每原子数兆电子伏的能量差，并表现出强大的声子的稳定性。同样，通过与其他已知相进行比较，新相显示出相当宽的带隙和较小的电子有效质量。该PMC 2 ₁相节目0.277 C M计算出的自发极化^-2，接近的ε/κ -镓₂ ö ₃。全身结构的搜索也建立之间的结构关系ε -镓₂ ö ₃和κ -镓₂ ö₃，以及电子特性如何随多态相变而变化。