Fully first-principles screened-exchange LDA calculations of excited states and optical properties of III-V semiconductors

Optical properties, such as the imaginary part of the dielectric function, index of refraction, reflectivity, and absorption coefficient, [ε ₂(ω),n(ω),k(ω),R(ω),α(ω)] of some III-V semiconductors (InAs, InSb, GaSb, and AlSb), are determined using our highly precise full-potential linearized augmented plane wave method with the screened-exchange local density approximation (sX-LDA) solved self-consistently and with spin-orbit coupling included. Here ε ₂(ω) is calculated using the longitudinal expression with full e ^iq·r matrix elements due to the nonlocality of the potential in the sX-LDA method, and its structure is analyzed with band structures and consideration of interband transitions. The critical point energies are also studied in comparison with experiment. The results of these fully first-principles calculations (no scissor operator or semiempirical inputs) show good agreement of the peak positions in ε ₂(ω) , n(ω)+ik(ω), R(ω), α(ω) and critical point energies with experiments.