Mechanical stability, electronic, and optical properties of bulk and (001)-surfaces of Sr2RuO4-xFx quaternary alloy.

Abstract

The DFT- based calculations are used to investigate the mechanical, electronic, and optical characteristics of Sr2RuO4-xFx (x = 0, 2) to elucidate the applications in renewable energy devices. The Voigt–Reuss–Hill approximation method is applied to analyze the elastic constants, Poisson ratio, bulk, shear, and Young modulus. The results demonstrate that the Sr2RuO4 and Sr2RuO2F2 tetragonal phases are mechanically stable because the elastic constants satisfy Born's mechanical stability condition. Then, Sr2RuO2F2 thin films are simulated in the (0 0 1) direction with a broad vacuum of 2.5 nm across the z-plane to eliminate the interlayer interactions. The relative stability and the feasibility of the synthesis of the different numbers of layers are proved by the positive values obtained for the surface energies. The thin films exhibited narrower band gaps compared with their bulk counterparts; gaps increased with increasing thickness of the thin films and the absorption ability is improved in the visible light (380∼790 nm). The findings suggest that all the studies’ structures with various thicknesses are significantly absorbent and productive with an optical absorption that exceeds 104 cm−1 in the visible range (λ ∼ 550 nm). Hence, the Sr2RuO2F2 films may be promising candidates in advanced optoelectronic and solar cell applications.