Enhancement of superconductivity in W5Si3 with Tc ∼ 6.2 K by P-doping

The effects of phosphorus doping on the prototypical transition metal silicide W5Si3, predicted to host a topologically nontrivial band structure and exhibit superconductivity below its critical temperature (T-c) of 2.7 K, have been investigated. Upon P-doping, the lattice parameter a decreases and c increases for W5Si3-xPx up to x = 0.7. Notably, T-c and the upper critical field of W5Si3-xPx are enhanced by over twofold as x increases, achieving 6.2 K and 5.5 T at x = 0.7, respectively. This enhancement in bulk superconductivity is attributed to a shift of the Fermi level toward a local maximum in the density of states upon P-doping, as indicated by the first-principles calculations. Our results suggest an effective doping strategy which significantly enhances the superconductivity in W5Si3. The emerging W5Si3-type superconductors offer a promising platform for realizing possible topological superconductivity.