Tunable Superconductivity in Phosphorus‐Doped Topological Transition‐Metal Germanide Mo₅Ge₃

Abstract

The effect of phosphorus doping in the transition metal germanide Mo5Ge3, which is predicted to be a nodal line semimetal and exhibits superconductivity below Tc = 0.75 K, is studied. It is found that Mo5Ge3−x$_{3-x}$Px retains the tetragonal W5Si3‐type structure up to x = 1.0, and the incorporation of phosphorus leads to a shrinkage of the unit cell volume. Remarkably, Tc of Mo5Ge3−x$_{3-x}$Px is enhanced by more than one order of magnitude with increasing x, reaching 8.24 K at x = 1.0. This enhancement is attributed to the increases in both the density of states at the Fermi level and electron–phonon coupling strength. Theoretical calculations show that the phosphorus doping leads to a nearly rigid‐band shift of the Fermi level into a local maximum of the density of states. This study unveils that transition metal germanides offer an emerging platform to study the interplay between superconductivity and nontrivial band topology.