Electronic and optical properties of Ti3AC2 (A=Sn, Ge, Si) MAX phases by first-principles calculations

In order to better understand the physical properties of Ti₃AC₂ (A = Sn, Ge, Si) ternary carbides and to provide a theoretical basis for their applications, we have calculated the electronic structure and optical properties of Ti₃AC₂ (A = Sn, Ge, Si) by first principles. The results, based on the formation enthalpy and binding energy calculations, indicate that Ti₃AC₂ (A = Sn, Ge, Si) is thermodynamically and kinetically stable. Charge density differences and bond residence numbers further reveal the formation of a strong Ti-C bond in Ti₃AC₂ (A = Sn, Ge, Si), attributed to the hybridization between the C-s and Ti-d states. Finally, by analyzing the optical properties such as dielectric function, reflectivity and absorption coefficient, the results show that Ti₃AC₂ (A = Sn, Ge, Si) exhibits optical anisotropy.