First-principles Calculations to Investigate Emerging Double Perovskites K2NaMoX6 (X=Cl, I) Compounds for Magnetic and Optoelectronic Applications

Abstract

In the present work, the structural, electronic, optical and mechanical properties of lead free halide double perovskites (HDPs) K2NaMoX6 (X = I, Cl) are addressed by using density functional theory (DFT). The optimized structural parameters validate the stability of the magnetic states of K2NaMoX6 (X = I, Cl) compounds with magnetic moment of 3.0006 and 3.00001 μB, respectively. The stability of cubic phase of both compounds is justified by tolerance factor. Spin resolved band structure (BS) and density of states (DOS) demonstrate that K2NaMoCl6 and K2NaMoI6 are direct-gap semiconducting materials. Moreover, the computed elastic properties reveal the ductile and anisotropic nature of both compounds. The optical features such as, the absorption coefficient (α(ω)), real ϵ1(ω) and imaginary parts ϵ2(ω) of the dielectric function, optical conductivity (σ(ω)), refractive index (n(ω)), extinction coefficient (k(ω)) and reflectivity (R(ω)) are also computed. In optoelectronic devices, these HDPs have intriguing uses due to the excessive α(ω) and small reflection in the visible-UV span.