First-principles investigation of physical properties of transition metal-based ternary TM5Si3C (TM = Nb, Mo, Ta, W) silicides of nowotny phase

Abstract

In this work, the structural, electronic, mechanical, elastic anisotropy, thermodynamic, and optical properties of TM5Si3C silicides have been examined using first-principles calculations. All studied silicides fulfill the structural stability criteria. Computed mechanical properties reveal the ductile nature of Mo5Si3C, Nb5Si3C, and W5Si3C silicides, while Ta5Si3C silicide is brittle in character. Elastic anisotropy plots, including 2D and 3D, show highly anisotropic behaviour. The ascertained electronic and dielectric properties substantiate the conductive nature of all these silicides. All silicides in the visible region have an average reflectivity of 46 %, making them ideal for coatings to reduce solar heating. Debye temperature, melting point, thermal conductivity, and Gr u¨ neisen constant has also been investigated in current work. Thermodynamic properties have been computed at different pressure and temperature values including bulk modulus (B), volume (V), thermal expansion coefficient (α), Debye temperature (θD), and lattice heat capacity (Cv). The probed results of TM5Si3C ternary silicides demonstrate their viability for applications at elevated temperatures and as well as solar reflectors. Our findings may provide a gateway for exploring new ternary silicides and can act as an efficient, cost-effective guide for experimentalists.