The electronic structure and optical properties of XSi(XÂ =Â Fe,Ru,Os): A first principles investigation within the modified Becke-Johnson exchange potential plus LDA

► Reproduce of band gap for XSi(X = Fe,Ru,Os) with gap of ∼10−1 eV. ► Using the mBJ + LDA first principles in comparison with GGA and LDA. ► Theoretical optical conductivity is in agreement with the measurement.