Electron–phonon coupling of the Ti3Sb compound

Abstract

Using the first-principles method based on density functional theory, we investigate the electronic, mechanical, phononic, superconducting, and topological properties of the A15 superconductor Ti3Sb with/without the inclusion of spin–orbit coupling (SOC). We find that the calculated elastic constants satisfy the Born stability criteria and the ductile nature of Ti3Sb. The result of phonon calculations reveals that the Pm3¯n structure is dynamically stable. Sb atoms are dominated in the low-frequency region due to the mass difference between Ti and Sb from partial phonon calculations. Our electronic structure calculations show that Ti3Sb has metallic band structures with Ti-d bands near the Fermi energy. The electron–phonon coupling constant (λ≃0.80) indicates that Ti3Sb has strong electron–phonon coupling. The critical temperature (Tcμ⋆=0.10) is found to be 6.24 and 6.56 K with and without the SOC effect, respectively. Due to Ti’s relatively small SOC strength, we do not find evidence of non-trivial topology in contrast to Ta compounds such as Ta3Sb.