Calculation of the Energy Band Structure of the β-SiC Crystal by the Orthogonalized Plane Wave Method

Abstract

The energy band structure of the β- (zincblende-type) SiC crystal is worked by the orthogonalized plane wave (OPW) method. Since this crystal will be the typical one of the IV–IV compounds, the results of calculation for its electronic structure will be useful for systematic understanding of the transitions of the electron-behavior from the group-IV valence-crystals to the III–V compounds etc.. Our results show that the conduction band-minima occur at X -point or its immediate neighbor, while the valence band-maximum perhaps at \(\varGamma\)-point. Hence the indirect interband-transitions in the long wave limit will be expected to occur between these two states with the energy difference of 2.2 ev, and the direct interband-transitions at X -point will take place at a photon energy of 6.3 ev. Further the approximate charge-distribution in the crystal is worked by making use of the obtained \(\varGamma\)-valence eigenfunctions, which result seems to show that the electrons in its \(\vec{k}{=}0\) levels of the β-SiC will be approximately a covalent-like distribution as far as \(\varGamma\)-eigenfunctions do concern. Finally, an idea is proposed to improve the slow-convergence of the OPW method for conduction bands of insulators. Its practical application is now in progress for the β-SiC.