Electronic and Phononic Contributions to Superconductivity of Pm-3m MRu₃ (M = V, Nb, and Ta)

Abstract

Various transition metal compounds were reported to exhibit superconducting properties. Inspired by these findings, we conducted a computational investigation into the density of states, Fermi surface nesting functions, vibrations, and superconductivity of Pm-3m MRu 3 by using first-principles calculations. Calculated results reveal that superconducting transition temperatures (T c ) of Pm-3m VRu 3 , NbRu 3 , and TaRu 3 are 14.2, 9.8, and 8.2 K, respectively. The Fermi nesting function and line widths indicate that VRu 3 has a bigger electron−phonon matrix than NbRu 3 and TaRu 3 . The superconductivity of Pm-3m MRu 3 is attributed to a strong interaction between Ru-d electrons near the Fermi energy and the phonons of coupled M-Ru vibrations. The factors resulting in the difference in T c of MRu 3 are the varying strengths of the coupling between the M-d electrons around the Fermi energy and the phonons associated with M-Ru-coupled vibrations as well as the atomic vibrations of VB group atoms. The findings of the present study offer significant insights that can inform future research and design of new superconducting materials based on transition metal compounds belonging to the same family.