WikiEdge:ArXiv速遞/2025-03-03

摘要

• 原文標題：Investigation of O interstitial diffusion in $β$-Ga$_2$O$_3$: direct approach via master diffusion equations
• 中文標題：$β$-Ga$_2$O$_3$中氧間隙擴散的研究：通過主擴散方程的直接方法
• 發布日期：2025-03-03 16:54:55+00:00
• 作者：Grace McKnight, Channyung Lee, Elif Ertekin
• 分類：cond-mat.mtrl-sci, physics.app-ph, physics.comp-ph
• 原文鏈接：http://arxiv.org/abs/2503.01735v1

原文摘要：Monoclinic $\beta$-Ga$_2$O$_3$, a promising wide band gap semiconducting material, exhibits complex, anisotropic diffusional characteristics and mass transport behavior as a results of its low symmetry crystal structure. From first-principles calculations combined with master diffusion equations, we determine three-dimensional diffusion tensors for neutral ($\text{O}_{\text{i}}^{0}$) and 2- charged oxygen interstitials ($\text{O}_{\text{i}}^{2-}$). Systematic exploration of the configurational space identifies stable configurations in these two dominant charge states and their corresponding formation energies. By connecting every pair of low-energy configurations considering both interstitial or interstitialcy hops, we construct three-dimensional diffusion networks and evaluate hopping barriers of all transition pathways in networks. Combining the collection of (i) defect configurations and their formation energies and (ii) the hopping barriers that link them, we construct and solve the master diffusion equations for $\text{O}_{\text{i}}^{0}$ and $\text{O}_{\text{i}}^{2-}$ separately through the Onsager approach, resulting in respective three-dimensional diffusion tensors D$_{\text{O}_{\text{i}}}^{0}$ and D$_{\text{O}_{\text{i}}}^{2-}$. Both $\text{O}_{\text{i}}^{0}$ and $\text{O}_{\text{i}}^{2-}$ present the fastest diffusion along the $b$-axis, demonstrating significant anisotropy. The predicted self-diffusivities along [100] and [$\overline{2}01$] align well with previously reported values from isotopically labeled oxygen tracer experiments, highlighting the reliability of the approach in capturing complex diffusion mechanisms.

中文摘要：單斜晶系的$\beta$-Ga$_2$O$_3$是一種有前景的寬帶隙半導體材料，由於其低對稱性的晶體結構，表現出複雜的各向異性擴散特性和質量傳輸行為。通過第一性原理計算結合主擴散方程，我們確定了中性氧間隙（$\text{O}_{\text{i}}^{0}$）和帶2-電荷的氧間隙（$\text{O}_{\text{i}}^{2-}$）的三維擴散張量。通過對構型空間的系統探索，我們識別了這兩種主要電荷態的穩定構型及其相應的形成能。通過考慮間隙或間隙跳躍，連接每一對低能構型，我們構建了三維擴散網絡，並評估了網絡中所有過渡路徑的跳躍勢壘。結合（i）缺陷構型及其形成能和（ii）連接它們的跳躍勢壘，我們通過Onsager方法分別構建並求解了$\text{O}_{\text{i}}^{0}$和$\text{O}_{\text{i}}^{2-}$的主擴散方程，得到了相應的三維擴散張量D$_{\text{O}_{\text{i}}}^{0}$和D$_{\text{O}_{\text{i}}}^{2-}$。$\text{O}_{\text{i}}^{0}$和$\text{O}_{\text{i}}^{2-}$都表現出沿$b$軸的最快擴散，顯示出顯著的各向異性。沿[100]和[$\overline{2}01$]方向預測的自擴散係數與之前報道的同位素標記氧示蹤實驗值吻合良好，突出了該方法在捕捉複雜擴散機制方面的可靠性。