β-C3N4,β-Si3N4和β-Ge3N4的能带结构

采用基于密度泛函理论的线性丸盒轨道原子球近似(LMTO-ASA)从头计算方法,研究了β-C₃N₄,β-Si₃N₄和β-Ge₃N₄的能带结构,得到了它们的能隙分别为:4.1751,5.1788和4.0279eV。对于β-C₃N₄,由于N的部分2p电子占据了非键轨道,禁带宽度较窄;对于β-Si₃N_{4关键词：}

BAND STRUCTURAL PROPERTIES OF β-C3N4, β-Si3N4 AND β-Ge3N4

The electronic energy bands of a series of β phases of carbon nitride, silicon nitride and germanium nitride have been calculated using a first-principle linear combination of muffin-tin orbital method with the atomic-sphere approximation(LMTO-ASA). The band gaps obtained for the three compounds are 4. 1751,5. 1788 and 4. 0279 eV, respectively. For β-C₃N₄ ,the nitrogen 2p orbitals plays an important role in the top of valence band(VB) due to its non-bonding. For -β-Si₃N₄,the silicon 3d orbitals plays an important role both in the VB and in the conduction band(CB). Its band gap is indirect which is in agreement with other calculated results. For β-Ge₃N₄,the germanium 3d orbitals preserve the characteristics of atomic orbitals and give very little contributions to other VBs and CB. Its 4d empty orbitals play a role analogue to 3d of Si of β-Si₃N₄. This is the frist theoretical study reported on the electronic structure of β-Ge₃N₄.