Electronic Structure and Optical Properties of C-Doped Ca₂Si

A first-principle method is used to calculate the geometric structure, energy band structure, electronic state density, and optical properties of C-doped Ca₂Si. Results show that volume of Ca₂Si decreases, and band gap increases after doping with C. The optical properties of Ca₂Si after C doping change as follows: ε₁(0) and refractivity index increase, whereas ε₂(ω), extinction coefficient, absorption, and reflectivity decrease. (paper)