物理化学学报 >> 2017, Vol. 33 >> Issue (3): 548-553.doi: 10.3866/PKU.WHXB201612081

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单壁AlAs (111)纳米管结构和电子性质的密度泛函理论研究

王玮,谭凯*()   

  • 收稿日期:2016-09-12 发布日期:2017-03-07
  • 通讯作者: 谭凯 E-mail:ktan@xmu.edu.cn
  • 基金资助:
    国家自然科学基金(21573182)

Structure and Electronic Properties of Single Walled Nanotubes from AlAs (111) Sheets: A DFT Study

Wei WANG,Kai TAN*()   

  • Received:2016-09-12 Published:2017-03-07
  • Contact: Kai TAN E-mail:ktan@xmu.edu.cn
  • Supported by:
    The project was supported by the National Natural Science Foundation of China(21573182)

摘要:

通过卷曲立方AlAs(111)单层片(sheets)构造了一系列(n,0)和(nm)一维单壁纳米管。用周期性密度泛函理论(DFT)计算并比较了不同类型AlAs纳米管在几何结构、能量及电子性质等方面的差别。计算结果表明锯齿型和椅型纳米管应变能均为负值,并随着管径变大而逐渐变小。然而,它们的带隙相当不同:椅型纳米管为间接带隙,随着管径的增大而带隙减小;锯齿型纳米管为直接带隙,管径为1.87 nm时存在着一个极大带隙值(2.11 eV)。这种不同主要源于锯齿型纳米管铝原子间3p轨道的耦合贡献。

关键词: 密度泛函理论, 砷化铝, 锯齿型, 椅型, 纳米管

Abstract:

A series of AlAs nanotubes (NTs) can be formed by rolling up two dimensional periodic (111) single layer sheets, namely (n, 0) and (n, m) nanotubes. Optimized parameters of the atomic arrangement, energy levels and electronic structure of corresponding nanotubes of different types were calculated and compared by the density functional theory (DFT) method. The calculated results showed that strain energies (Es) are negative over most of the diameter range for the (n, 0) and (n, m) series, indicating that these NTs are more stable than a planar AlAs (111) single layer. The strain energy gradually decreases with increasing diameter. The calculated electronic band structures and density of states profiles reveal that the indirect band gaps (Eg) of armchair AlAs nanotubes gradually decreases with increasing diameter, which is distinct behavior from the zigzag nanotubes. The zigzag AlAs nanotubes feature a direct Eg with a peak value (2.11 eV) for a tube of radius 1.87 nm. The origin of the differences in band gaps could be attributed to the p-p coupling interaction between Al 3p orbitals in the conduction band of the AlAs zigzag nanotube.

Key words: Density functional theory, AlAs, Zigzag, Armchair, Nanotube

MSC2000: 

  • O641