Pressure influenced electronic phase transition, mechanical, optoelectronic, and transport characteristics of double perovskite Rb2AgSbCl6: A first-principles investigation

Abstract

In this work, we used density functional theory (DFT) simulations to investigate the structural, elastic, electronic, optical, and transport characteristics of pressure-induced Rb2AgSbCl6. By calculating the octahedral and the tolerance factors, the phase stability has been verified. The calculated formation energy and Gibbs free energy values have demonstrated the thermodynamic stability of the material. The outcomes of the mechanical behavior analysis revealed that the pressure-driven Rb2AgSbCl6 is mechanically stable and sustains ductility as well as anisotropy. Additionally, as the pressure is increased from 0 GPa to 100 GPa, the band gap has been reduced from 2.64 eV to 0 eV. The hydrostatic pressure of 100 GPa was the critical pressure at which the material revealed a metallic nature. The optical properties such as absorbance and optical conductivity shift towards lower energy and comparatively higher at increased pressure with minimal energy loss. The thermoelectric characteristics are examined utilizing the BoltzTraP code at different pressures. The figure of merit (ZT) value was increased from 0.76 to 0.80 with the increase in pressure at room temperature. These characteristics render pressure-influenced Rb2AgSbCl6 favorable candidates for utilization in solar cells as well as thermoelectric devices.