New development of self-interaction corrected DFT for extended systems applied to the calculation of native defects in 3C-SiC

We recently developed a framework for implementing a scaled self-interaction corrected density functional theory (DFT-SIC) into pseudo-potential plane-wave DFT. The technique implements the original method of Perdew and Zunger by direct minimization of the DFT-SIC total energy functional. By using maximally localized Wannier functions, DFT-SIC calculation can be carried out efficiently even for extended systems. Using this new development, the formation energies of defects in 3C-SiC ( silicon carbide) were calculated and compared to more standard DFT calculations. Differences of up to 1 eV were seen between DFT and DFT-SIC calculations of the formation energies. When compared to DFT, DFT-SIC produced less-stable vacancies and silicon interstitials, and more stable antisites and carbon interstitials. The most favourable interstitials were found to be C interstitials in a C+-C < 100 > dumbbell configuration, with the formation energy of 5.91 eV with DFT and 5.65 eV with DFT-SIC. Si interstitials were not as stable as C interstitials. The most favourable Si interstitial was found to be Si tetrahedral surrounded by four C atoms, with a formation energy of 7.65 eV with DFT and 8.71 eV with DFT-SIC.