The carbon-substitutional-carbon-interstitial (CsCi) defect pair in silicon from hybrid functional calculations

Abstract

Using both the Perdew–Burke–Ernzerhof (PBE) functional and the hybrid functional of Heyd–Scuseria– Ernzerhof (HSE06), the metastability of the carbon-substitutional–carbon-interstitial (CsCi) defect in silicon has been investigated within density functional theory using the two experimentally proposed configurations of the defect. While the PBE functional predicted the defect complex to have both donor and acceptor levels, it did not predict any form of charge-state controlled metastability as was observed experimentally. In the case of HSE06 functional, the defect was found to exhibit charge-state controlled metastability in the 0 and 1 charge states with no metastability predicted for +1 charge state. The calculated binding energies for the neutral charge state indicate that the defect is a stable bound defect complex.