First‐Principles Investigation of Electronic, Mechanical, Thermal, and Optical Properties of Janus TaSeS Monolayer

First‐principles‐based density functional theory simulations have been carried out to investigate the electronic and physical properties of Janus TaSeS monolayer in 1H‐phase. The optimized structure shows non‐magnetic ground state with lattice parameter of 6.35 Å. The negative values of cohesive (−6.51 eV) and formation (−1.26 eV) energies reveal its chemical stability, and the positive values of frequencies in acoustic branch indicate its dynamical stability. The metallic behavior of the material is confirmed due to contribution of dz 2 ‐orbital near the Fermi level, a characteristic of cold metallic‐like materials. The elastic constants satisfy Born–Huang criteria, confirming the mechanical stability of the material. The value of Poisson's ratio (0.36) confirms the ductile behavior. The 2D polar plots show isotropic properties for both in‐plane stiffness and Poisson's ratio. The onset of nonlinear elastic behavior due to the effect of both uniaxial and biaxial strain is analyzed. The variation of C p and C v within the Dulong–Petit limit is in agreement with the Debye T 3 ‐law. The analysis of optical properties within the range of 0–14 eV photon energy reflects the applications of TaSeS in various functionalities within ultraviolet to infrared regions.