First-principles study of structural, elastic, electronic, thermodynamic and optical properties of Sc3SnX (X = B, C)

Abstract

We have calculated the structural, elastic, electronic, thermodynamic and optical properties of Sc3SnX (X = B, C) using first-principles density functional theory (DFT). The optimized structural parameters are found to be in good agreement with the experimental results of Sc3SnX1-y (X = B, C). The mechanical stability of these compounds have been theoretically confirmed using Born criteria. Both materials are shown to be brittle in nature. The electronic band structures and electronic density of states (EDOS) are calculated. The electronic band structures show metallic characteristics with contribution predominantly from the Sc 3d orbital. The computed Peierls stress reveal that movement may occur much slowly compared to a selection of MAX phases. The calculated Vickers hardness for Sc3SnB and Sc3SnC are 4.45 and 4.04 GPa, respectively. The bulk modulus, specific heats, thermal expansion coefficient and Debye temperature are calculated as a function of temperature using the quasi-harmonic Debye model with phononic effects. Moreover optical functions are calculated and discussed for the first time. The reflectivity is found to be high in the IR-UV regions up to ∼12 eV for both Sc3SnB and Sc3SnC thus showing promise as good coating materials.