物理化学学报 >> 1995, Vol. 11 >> Issue (02): 131-134.doi: 10.3866/PKU.WHXB19950207

研究论文 上一篇    下一篇

晶态Ca3C60与Ca5C60的能带结构研究

曹阳, 陈良进, 陈波, 冯建文   

  1. 苏州大学化学系|苏州 215006
  • 收稿日期:1994-01-03 修回日期:1994-03-15 发布日期:1995-02-15
  • 通讯作者: 曹阳

Band Structure Studies for Crystalline Ca3C60 and Ca5C60

Cao Yang, Chen Liang-Jin, Chen Bo, Feng Jian-Wen   

  1. Department of Chemistry,Suzhou University,Suzhou 215006
  • Received:1994-01-03 Revised:1994-03-15 Published:1995-02-15
  • Contact: Cao Yang

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摘要：

用三维EHMO晶体轨道程序分别对Ca3C60，Ca5C60进行了能带结构的计算．计算结果表明，Ca3C60没有导电性，能隙约为0．9eV；而在Ca5C60的能带结构中，费米面刚好穿过半满带，表明Ca5C60是导体；同时在费米面附近有较大的态密度值，表明Ca5C60与K3C60等类似，具有较高的超导转变温度．电荷分析表明，在这两种情况下，钙原子的4s电子基本上全转移到C60上，C60分子可形成一个稳定的带6到10个电子的负离子．

关键词: 掺杂C60, 能带结构, EHMO

Abstract:

 Three dimensional EHMO crystal orbital calculations for crystalline Ca3C60 and Ca5C60 are reported. The ground state of partially doped Ca3C60 is found to be insulating with an indirect energy gap of 0.5eV. In contrast, Ca5C60 forms a metallic conducting phase with a set of three half-filled bands crossing the Fermi level which is found to be located close to the peak of the density of state. The character of crystal orbitals near the Fermi-level for both Ca3C60 and Ca5C60 is completely carbon-like. In both cases, the Ca atoms are almost fully ionized and C60 molecules can form a stable negative charge state with six to ten additional electrons. The projected DOS of Ca atoms near the Fermi-level and the overlap populations between Ca and C are neglectible.

Key words: Doped C60, Band sructure, EHMO