Effect of guest atoms on structural properties, electronics structure and optical spectra of BxCo4-XSb12 (X=0 or 1, B = Fe or Al) skutterudites

This work examines the density functional theory calculation of the structural, electronics and optical properties of BxCo4-xSb12 alloys from the first principle calculation with quantum expresso via the generalized gradient approximation and Perdew-Burke-Ernzerhop exchange-correlation functional. The lattice parameter, electronic band structure, density of state and projected density of state are evaluated and the results are compared to the theoretical and experimental data available for Co4-xSb12. The electronic band structures revealed a direct band gap of 0.78 eV and 0.80 eV for Co4-xSb12 and FeCo3Sb12 respectively while AlCo3Sb12 shows an indirect band gap of 0.13 eV. However, the density of state has the maxima peaks at -1.84 eV, -1.23 eV and -1.37 eV for Co4Sb12, FeCo3Sb12 and AlCo3Sb12 in order. Based on the projected density of state analysis, electronic states are dominated by Co-3d orbital for both compounds. For optical properties, random-phase approximation technique is used. The implementation approach is based on a multi-particle scheme that gives high accuracy compared to simulations with single particle dielectric tensor. A stronger optical responses are observed between infrared and visible region (low energy region) which indicate the nanostructure of BxCo4-xSb12 alloys. The results obtained verify the effectiveness and efficiency of BxCo4-xSb12 compounds for wave guide, photonic circuit design and nanoelectronics applications.

Automated summary

This study investigates the structural, electronic, and optical properties of BxCo4-xSb12 alloys using density functional theory calculations. The results show variations in electronic band gaps and density of states among different compounds, with Co-3d orbitals dominating the electronic states. Optical properties suggest strong responses in the infrared and visible region, indicating the potential nanostructure of BxCo4-xSb12 alloys for applications in wave guides, photonic circuits, and nanoelectronics.