中国物理B ›› 2017, Vol. 26 ›› Issue (4): 46101-046101.doi: 10.1088/1674-1056/26/4/046101

• CONDENSED MATTER: STRUCTURAL, MECHANICAL, AND THERMAL PROPERTIES • 上一篇    下一篇

Theoretical prediction of new C-Si alloys in C2/m-20 structure

Xiangyang Xu(徐向阳), Changchun Chai(柴常春), Qingyang Fan(樊庆扬), Yintang Yang(杨银堂)   

  1. State Key Discipline Laboratory of Wide BandGap Semiconductor Technology, School of Microelectronics, Xidian University, Xi'an 710071, China
  • 收稿日期:2016-12-04 修回日期:2017-01-09 出版日期:2017-04-05 发布日期:2017-04-05
  • 通讯作者: Qingyang Fan E-mail:qyfan_xidian@163.com
  • 基金资助:
    Project supported by the National Natural Science Foundation of China (Grant No. 61474089) and the Open Fund of Key Laboratory of Complex Electromagnetic Environment Science and Technology, China Academy of Engineering Physics (Grant No. 2015-0214.XY.K).

Theoretical prediction of new C-Si alloys in C2/m-20 structure

Xiangyang Xu(徐向阳), Changchun Chai(柴常春), Qingyang Fan(樊庆扬), Yintang Yang(杨银堂)   

  1. State Key Discipline Laboratory of Wide BandGap Semiconductor Technology, School of Microelectronics, Xidian University, Xi'an 710071, China
  • Received:2016-12-04 Revised:2017-01-09 Online:2017-04-05 Published:2017-04-05
  • Contact: Qingyang Fan E-mail:qyfan_xidian@163.com
  • Supported by:
    Project supported by the National Natural Science Foundation of China (Grant No. 61474089) and the Open Fund of Key Laboratory of Complex Electromagnetic Environment Science and Technology, China Academy of Engineering Physics (Grant No. 2015-0214.XY.K).

摘要: We study structural, mechanical, and electronic properties of C20, Si20 and their alloys (C16Si4, C12Si8, C8Si12, and C4Si16) in C2/m structure by using density functional theory (DFT) based on first-principles calculations. The obtained elastic constants and the phonon spectra reveal mechanical and dynamic stability. The calculated formation enthalpy shows that the C-Si alloys might exist at a specified high temperature scale. The ratio of B/G and Poisson's ratio indicate that these C-Si alloys in C2/m-20 structure are all brittle. The elastic anisotropic properties derived by bulk modulus and shear modulus show slight anisotropy. In addition, the band structures and density of states are also depicted, which reveal that C20, C16Si4, and Si20 are indirect band gap semiconductors, while C8Si12 and C4Si16 are semi-metallic alloys. Notably, a direct band gap semiconductor (C12Si8) is obtained by doping two indirect band gap semiconductors (C20 and Si20).

关键词: C-Si alloys, mechanical properties, band structure, direct band gap semiconductor

Abstract: We study structural, mechanical, and electronic properties of C20, Si20 and their alloys (C16Si4, C12Si8, C8Si12, and C4Si16) in C2/m structure by using density functional theory (DFT) based on first-principles calculations. The obtained elastic constants and the phonon spectra reveal mechanical and dynamic stability. The calculated formation enthalpy shows that the C-Si alloys might exist at a specified high temperature scale. The ratio of B/G and Poisson's ratio indicate that these C-Si alloys in C2/m-20 structure are all brittle. The elastic anisotropic properties derived by bulk modulus and shear modulus show slight anisotropy. In addition, the band structures and density of states are also depicted, which reveal that C20, C16Si4, and Si20 are indirect band gap semiconductors, while C8Si12 and C4Si16 are semi-metallic alloys. Notably, a direct band gap semiconductor (C12Si8) is obtained by doping two indirect band gap semiconductors (C20 and Si20).

Key words: C-Si alloys, mechanical properties, band structure, direct band gap semiconductor

中图分类号:  (Structure of bulk crystals)

  • 61.50.-f
61.50.Ah (Theory of crystal structure, crystal symmetry; calculations and modeling) 71.20.Nr (Semiconductor compounds) 71.55.Cn (Elemental semiconductors)