Electronic, Optical, and Thermoelectric Qualities of Sr ₂ p ₇ br Double Zintl Salt with Heptaphosphanortricyclane Configuration: A Promising Candidate for Thermoelectric and Photonic Devices

Abstract

Abstract In this investigation, the structural, electronic, optical, and thermoelectric qualities of Sr 2 P 7 Br, a double Zintl salt with a heptaphosphanortricyclane configuration, were assessed using the first‐principles FP‐LAPW approach. The exchange‐correlation interactions were simulated using the GGA‐PBEsol method to analyze the structural properties, whereas the TB‐mBJ functional was utilized to assess the electronic, optical, and thermoelectric features. The Birch–Murnaghan equation of state was used to fit the total energy versus unit cell volume in order to determine the relaxed lattice parameter, bulk modulus, and its pressure derivative. The calculated equilibrium structural parameters and bulk modulus agree with the corresponding experimental and theoretical values. Based on the results of the computed density of states and band structure, Sr 2 P 7 Br is classed as a wide bandgap semiconductor with an indirect bandgap (R‐M) of 4.14 eV. The QTAIM descriptors computed at critical points forecast the covalent and ionic characteristics of the bonds between the compound's atoms. The optical coefficients, comprising the complex dielectric function, reflectivity, complex refractive index, absorption coefficient, and electron energy loss, were examined across an energy spectrum of 0–40 eV. The thermoelectric coefficients were determined utilizing the semi‐classical Boltzmann transport model, assuming that the relaxation time remains constant. The results show that the figure of merit is about 0.9 at 600 K.