High-entropy silicide superconductors with W$_{5}$Si$_{3}$-type structure

We report the synthesis, crystal structure and physical properties of two new high-entropy silicides (HESs), namely (Nb$_{0.1}$Mo$_{0.3}$W$_{0.3}$Re$_{0.2}$Ru$_{0.1}$)$_{5}$Si$_{3}$ (Nb$_{0.2}$Mo$_{0.3}$W$_{0.3}$Re$_{0.1}$Ru$_{0.1}$)$_{5}$Si$_{3}$. Structural analysis indicates that both HESs consist a (nearly) single tetragonal W$_{5}$Si$_{3}$-type phase (space group $I$4/$mcm$) with disordered cation distribution. Electrical resistivity, magnetic susceptibility specific heat measurements show (Nb$_{0.2}$Mo$_{0.3}$W$_{0.3}$Re$_{0.1}$Ru$_{0.1}$)$_{5}$Si$_{3}$ are weakly coupled bulk superconductors, which represent first superconducting nonoxide ceramics. In particular, these have higher $T_{\rm c}$ values (3.2-3.3 K) compared those binary counterparts, their $B_{\rm c2}$(0)/$T_{\rm ratios largest among superconductors same structural type.