Commun. Comput. Phys., 8 (2010), pp. 289-303.


Theoretical Study on Structural Stability of Alloy Cages: A Case of Silicon-Doped Heterofullerenes

Xiaofeng Fan 1*, Zexuan Zhu 1, Lei Liu 1, Zexiang Shen 1, Jer-Lai Kuo 2

1 School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore.
2 School of Physical and Mathematical Sciences, Nanyang Technological University, Singapore 637371, Singapore; and Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, 10617, Taiwan.

Received 10 December 2009; Accepted (in revised version) 26 January 2010
Available online 12 March 2010
doi:10.4208/cicp.101209.260110a

Abstract

Structural stability and Si-substitution pattern in fullerene cage of C$_{60-n}$Si$_{n}$ are thoroughly investigated by integrating density functional calculations with a color-bond graph (CBG) model. We find that the parameterized CBG model with genetic algorithms can efficiently scan the large configuration space of alloy and therefore identify the low-energy region within the first-principles accuracy. Low-energy (stable) structures of C$_{60-n}$Si$_{n}$ in carbon-rich region ($1\le n \le 30$) were identified and the silicon atoms are found to tend to aggregate in the fullerene cage. The mixing energy of these low-energy structures is $\sim$ 35 meV/atom and insensitive to the Si concentration. We expect that these alloy fullerene cages can be synthesized experimentally at elevated temperatures.


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PACS: 71.15.Mb, 82.33.Fg, 71.15.Nc, 36.40.Qv, 73.61.Wp, 61.46.Bc
Key words: Structure of alloy cluster, density functional calculations, fullerene Alloys C$_{60-n}$Si$_{n}$ Heterofullerenes, genetic algorithms.

*Corresponding author.
Email: xffan@ntu.edu.sg (X. Fan), zhuzexuan@pmail.ntu.edu.sg (Z. Zhu), LiuLei@ntu.edu.sg (L. Liu), zexiang@ntu.edu.sg (Z. Shen), jlkuo@pub.iams.sinica.edu.tw (J.-L. Kuo)
 

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