First-Principles Study of Two-Dimensional Titanium Dioxides
First-Principles Study of Two-Dimensional Titanium Dioxides
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DOI：
10.1021/jp035017t
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发表时间：
2003-08
影响因子：
3.3
通讯作者：
Hisako Sato;K. Ono;T. Sasaki;A. Yamagishi
中科院分区：
文献类型：
--
作者：
Hisako Sato;K. Ono;T. Sasaki;A. Yamagishi
用密度泛函理论中的第一性原理计算方法研究了层状和单层锂镁石型二氧化钛(以下分别称为单层和层状)二氧化钛(以下简称S)。对其晶体结构、电子结构、介电性能和力学性能进行了研究。通过再现已知的块状TiO2多晶型(金红石和锐钛矿型)的实验性质，证实了本理论的有效性。对于单层锂镁石型二氧化钛，优化的结构参数与文献报道的Ti0.91O2或Cs0.7Ti1.825O4-0.175(-=空位)的剥离纳米片的数据吻合得很好。单层二氧化钛的稳定性略低于金红石型和锐钛矿型。在厚度小于1 nm的二维结构中，由于量子尺寸效应，单层二氧化钛的禁带宽度为3.15 eV，大于金红石和锐钛矿的禁带宽度。单层锂镁石型TiO2光催化剂的介电常数为h。
Stacked and single-layered lepidocrocite-type titanium dioxides (hereafter denoted as single-layered and stacked TiO2's, respectively) have been investigated by using first-principles calculations within density functional theory. The crystal structures, electronic structures, dielectric properties, and mechanical properties have been studied. The validity of the present theory was confirmed by reproducing the experimental properties of known bulk TiO2 polymorphs (rutile and anatase). As for a single-layered lepidocrocite-type TiO2, the optimized structural parameters agree well with the reported data of an exfoliated nanosheet of Ti0.91O2 or Cs0.7Ti1.825O4□0.175 (□ = vacancy). Single-layered TiO2 is slightly less stable than rutile and anatase. The band gap of single-layered TiO2 is 3.15 eV, which is larger than those of rutile and anatase due to a quantum size effect in a two-dimensional structure with a thickness less than 1 nm. The dielectric constant of the single-layered lepidocrocite-type TiO2 is h...