发表机构
Ivane Javakhishvili Tbilisi State University; New York City College of Technology, The City University of New York; The Graduate School and University Center, The City University of New York; Long Island University（伊万·贾瓦希什维利第比利斯国立大学; 纽约市立学院，纽约市立大学; 研究生院与大学中心，纽约市立大学; 长岛大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究通过第一性原理计算，明确Ga掺杂α-Al₂O₃的电子结构与带边特征，为含Ga氧化物纳米结构相关研究提供了化学分辨基准。
AI 中文摘要
我们开展了针对α-Al₂O₃基主体中Ga替位掺杂的第一性原理密度泛函理论研究，在不考虑几何量子限域的情况下分离出化学嵌入效应。采用含2个替位Ga原子的30原子α-Al₂O₃超胞，我们考察了三种不等价的Ga对构型，结合构型依赖的能量学、局域结构分析、Ga中心畸变度量以及电子结构计算，建立了局域配位畸变与带边改性之间的关系。能量上偏好的构型并非仅由Ga-O键膨胀决定，而是取决于主体晶格容纳替位Ga中心周围键长和键角畸变的能力。与纯α-Al₂O₃相比，Ga掺杂会缩小带隙且不产生带隙中态，主要改性导带流形，同时保留氧主导的价带边。带边电荷密度和电荷密度差图显示，电子响应仍局域在Ga中心配位环境周围。这些结果为理解超宽带隙氧化物中的Ga掺杂以及后续含Ga氧化物纳米结构的限域和界面效应研究建立了化学分辨的基准。
英文摘要
We present a first-principles density functional theory study of substitutional Ga incorporation in an $α$-Al$_2$O$_3$-derived host, isolating chemical embedding effects without explicit geometric quantum confinement. Using a 30-atom $α$-Al$_2$O$_3$ supercell with two substituted Ga atoms, we examine three nonequivalent Ga-pair configurations and combine configuration-dependent energetics, local structural analysis, Ga-centered distortion metrics, and electronic-structure calculations.% to establish the relationship between local coordination distortion and band-edge modification. The energetically preferred configuration is governed not solely by Ga--O bond expansion but by the ability of the host lattice to accommodate bond-length and angular distortions around substituted Ga centers. Ga incorporation narrows the band gap relative to pristine $α$-Al$_2$O$_3$ without generating mid-gap states, primarily modifying the conduction-band manifold while preserving the oxygen-dominated valence edge. Band-edge charge densities and charge-density-difference maps show that the electronic response remains localized around the Ga-centered coordination environment. These results establish a chemically resolved baseline for understanding Ga incorporation in ultrawide-band-gap oxides and for future studies of confinement and interface effects in Ga-containing oxide nanostructures.
Comments11 pages, 8 figures
