Role of transition metal based kagome lattice in the physical properties of LaIr5, LaIr3B2, LaIr3Ga2, LaRh3B2, and YRu3B2 superconductors

Recent research on kagome compounds has pointed out their multiple applications in diverse fields. Here, we have reported the physical properties of hexagonal superconductors LaIr5, LaIr3B2, LaIr3Ga2, LaRh3B2, and YRu3B2, in which transition metal atoms form a kagome lattice. In our ab initio calculations, we have employed the generalized gradient approximation of the density functional theory and the plane-wave ab initio pseudopotential method with and without spin-orbit coupling. Our electronic band structure calculations suggest that the Fermi surface is mostly governed by the d electrons of the transition metal atoms, while the remaining atoms do not play a significant role. Thus, the kagome arrangement of the transition metal atom lattice, which determines the energy and dispersion of the bands from the transition metal atom, has a strong impact effect on the electrons that become superconducting in all the studied kagome superconductors. Furthermore, our phonon and electron-phonon interaction calculations suggest that the propagation of phonons in the kagome lattice formed by transition metal atoms gives rise to superconductivity in all the studied compounds. These results signal that in all the studied compounds, the superconductivity stems from the kagome transition metal lattice and its formation is moderately more impacted with the inclusion of spin-orbit coupling for Ir-rich superconductors than others due to its higher nuclear charge than other transition metal atoms.