The detailed crystal and electronic structures of the cotunnite-type ZrO₂

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• 作者：Yan Zhang^a ; ^{yan.zhang@chd.edu.cn" class="auth_mail" title="E-mail the corresponding author} ; Li Duan^a ; Vincent Ji^b
• 关键词：A ; Oxides ; C ; Crystal structures ; C ; Electronic structures ; D ; Crystal-field splitting ; E ; First-principles
• 刊名：Solid State Communications
• 出版年：2016
• 出版时间：July 2016
• 年：2016
• 卷：239
• 期：Complete
• 页码：27-31
• 全文大小：1190 K

文摘

The detailed crystal and orbital-decomposed electronic structures of cotunnite-type ZrO₂ have been investigated by using the first-principles projector augmented wave (PAW) potential within the generalized gradient approximation as well as taking into account on-site Coulomb repulsive interaction (GGA+U). The optimized structure shows that the O_Iontainer hidden">${\mathrm{O}}_{\mathrm{I}}$ and e0395f5a" title="Click to view the MathML source">O_IIontainer hidden">${\mathrm{O}}_{\mathrm{II}}$ anions are surrounded by an arbitrary tetrahedron of four Zr cations and an arbitrary pentahedron of five Zr cations, respectively, in turn, the Zr cation is surrounded by an arbitrary tetrakaidecahedron formed by nine oxygen ligands. Although one more Zr cation is coordinated to e0395f5a" title="Click to view the MathML source">O_IIontainer hidden">${\mathrm{O}}_{\mathrm{II}}$, the larger bond lengths between e0395f5a" title="Click to view the MathML source">O_IIontainer hidden">${\mathrm{O}}_{\mathrm{II}}$ and its adjacent five Zr cations (d_OII−Zrontainer hidden">${\mathrm{d}}_{{\mathrm{O}}_{\mathrm{II}}-\mathrm{Zr}}$) than those between O_Iontainer hidden">${\mathrm{O}}_{\mathrm{I}}$ and its adjacent four Zr cations (e02fe89" title="Click to view the MathML source">d_OI−Zrontainer hidden">${\mathrm{d}}_{{\mathrm{O}}_{\mathrm{I}}-\mathrm{Zr}}$) makes density of states (DOS) of sontainer hidden">$\mathrm{s}$ and three pontainer hidden">$\mathrm{p}$ (p_xontainer hidden">${\mathit{p}}_{\mathit{x}}$, p_yontainer hidden">${\mathit{p}}_{\mathit{y}}$ and e0ec8994" title="Click to view the MathML source">p_zontainer hidden">${\mathit{p}}_{\mathit{z}}$) states of the e0395f5a" title="Click to view the MathML source">O_IIontainer hidden">${\mathrm{O}}_{\mathrm{II}}$ anion driving down in lower energy region and driving up in higher energy region. No crystal-field splitting is observed between three pontainer hidden">$\mathrm{p}$ (p_xontainer hidden">${\mathit{p}}_{\mathit{x}}$, p_yontainer hidden">${\mathit{p}}_{\mathit{y}}$ and e0ec8994" title="Click to view the MathML source">p_zontainer hidden">${\mathit{p}}_{\mathit{z}}$) states of anions O_Iontainer hidden">${\mathrm{O}}_{\mathrm{I}}$ and e0395f5a" title="Click to view the MathML source">O_IIontainer hidden">${\mathrm{O}}_{\mathrm{II}}$ (between three pontainer hidden">$\mathrm{p}$ (p_xontainer hidden">${\mathit{p}}_{\mathit{x}}$, p_yontainer hidden">${\mathit{p}}_{\mathit{y}}$ and e0ec8994" title="Click to view the MathML source">p_zontainer hidden">${\mathit{p}}_{\mathit{z}}$) states and five dontainer hidden">$\mathrm{d}$ (e00f45977" title="Click to view the MathML source">d_xyontainer hidden">${\mathit{d}}_{\mathit{xy}}$, d_yzontainer hidden">${\mathit{d}}_{\mathit{yz}}$, d_xzontainer hidden">${\mathit{d}}_{\mathit{xz}}$, d_z²ontainer hidden">${\mathit{d}}_{{\mathit{z}}^2}$ and d_x²-y²ontainer hidden">${\mathit{d}}_{{\mathit{x}}^2{-\mathit{y}}^2}$) states of cation Zr) is resulted from the arrangements of the surrounding cations (anions) do not have any symmetry. The additional covalent character upon Zr–O ionic bonds is attributed to the hybridization of itinerant Zr(5s) and less filled Zr(4d) states to the separated O(2s) and O(2p) states.