Comment on “Structural, electronic, and optical properties of the C-C complex in bulk silicon from first principles” [J. Appl. Phys. 123, 161421 (2018)]

Recently, Timerkaeva et al. [J. Appl. Phys. 123, 161421 (2018)] reported the results of a first principles study of the di-carbon (CsCi) complex in silicon. The authors have found that CsCi may occur in four configurations labeled A, B, C, and D. The C form is claimed to have the lowest energy of all four forms. Based on this, the authors suggest that the C form was misinterpreted as the B form in some experimental studies. This comment provides arguments that the conclusions of Timerkaeva et al. [J. Appl. Phys. 123, 161421 (2018)] do not match the well-known experimental results.