Crystal structural evolution of Ru ₃ Sn ₇ under pressure and its implication on possible electronic changes

Ru₃Sn₇, an intermetallic compound with advanced catalytic properties, exhibits a complex crystal structure and intriguing electronic properties, making it an attractive candidate for investigations under high-pressure (HP). The structural, vibrational and electronic band structure of this compound were investigated at HP up to ∼20 GPa using synchrotron x-ray powder diffraction, micro-Raman, and density functional theory, respectively. Despite the local structural changes implied by a discernible reduction in the compressibility and distinct slope changes in the pressure evolution of the symmetric stretching vibrations of the Ru and Sn atoms around 8 GPa, the cubic structure is found to be stable throughout the pressure range. In support, our calculated phonon dispersion relation confirmed the stability of the cubic phase till the highest pressures. A comprehensive analysis of the Raman spectrum reveals the signatures of the pressure induced sudden strengthening of electron-phonon coupling (EPC) as early as 3 GPa which is backed by a bounce in the phonon and electron density of states (DOS). Electronic structure calculations demonstrate that the metallic nature of Ru₃Sn₇is preserved in the studied pressure range with a minor redistribution of electronic DOS across the Fermi level (<i>E</i>_F). The band structure calculations predict intriguing changes in the electronic structure, revealing the pressure induced<i>d-p</i>hybridization through the high symmetry point of the Brillouin zone which is largely responsible for the observed reduction in the compressibility and enhancement of the EPC in Ru₃Sn₇.