Empirical pseudopotential band structure of 3C, 4H, and 6H SiC using transferable semiempirical Si and C model potentials - art. no. 045104

We present an approach to the empirical pseudopotential method (EPM) calcul ation of the band structure of SiC that overcomes the need for extensive ex perimental data. The method reduces the roughly 30 EPM fitting parameters n eeded to just two for 4H and one for 6H SiC. This allows fitting to the lim ited amount of experimental data available for these polytypes and the subs equent use of the EPM to calculate their bandstructure. A means of fitting to experimental effective masses through a nonlocal correction is also intr oduced. The procedure involves the construction of the empirical pseudopote ntial of diamond phase Si and C from local-model potentials based on the He ine and Abarenkov potential. These potentials successfully reproduce the ex perimental band energies around the band-gap region using one fitting param eter for each material. Once charge transfer is introduced, the potentials are then transferred to the heteropolar polytypes of SiC and the local pote ntial is fit to the experimental band energies using just one local fitting parameter for each polytype. A nonlocal correction. introducing a second a dditional fitting parameter. is then included to fit the experimental effec tive 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.