Empirical pseudopotential band structure of3C,4H,and6HSiC using transferable semiempirical Si and C model potentials

Abstract

We present an approach to the empirical pseudopotential method (EPM) calculation of the band structure of SiC that overcomes the need for extensive experimental data. The method reduces the roughly 30 EPM fitting parameters needed to just two for $4H$ and one for $6H$ SiC. This allows fitting to the limited amount of experimental data available for these polytypes and the subsequent use of the EPM to calculate their bandstructure. A means of fitting to experimental effective masses through a nonlocal correction is also introduced. The procedure involves the construction of the empirical pseudopotential of diamond phase Si and C from local-model potentials based on the Heine and Abarenkov potential. These potentials successfully reproduce the experimental band energies around the band-gap region using one fitting parameter for each material. Once charge transfer is introduced, the potentials are then transferred to the heteropolar polytypes of SiC and the local potential is fit to the experimental band energies using just one local fitting parameter for each polytype. A nonlocal correction, introducing a second additional fitting parameter, is then included to fit the experimental effective masses of $3C$ and $4H$ SiC. Since reasonable agreement with experimental effective mass measurements was obtained in $6H$ SiC with just the one local parameter, the nonlocal correction was not used.