We report the polycrystalline synthesis, crystal structure and superconducting properties of a new noncentrosymmetric compound ${\mathrm{Sc}}_6{\mathrm{RuSb}}_2$, which crystallizes in a hexagonal ${\mathrm{Fe}}_2\mathrm{P}$-type derived structure (space group $P\text{−}62m$, No. 189). Electrical resistivity, magnetic susceptibility, and specific heat measurements reveal a superconducting critical temperature $T_{\mathrm{c}}=3.95\mathrm{K}$ and an upper critical field ${\mu }_0{H}_{\mathrm{c}2}\left(0\right)=5.2\mathrm{T}$. The temperature dependence of the upper critical field suggests possible multiband superconducting behavior. The specific heat jump $\mathrm{\Delta }{C}_{\mathrm{e}}/{\gamma }_{\mathrm{n}}{\mathit{T}}_{\mathrm{c}}=1.65$ and the coupling strength $2{\mathrm{\Delta }}_0/k_{\mathrm{B}}{T}_{\mathrm{c}}=3.76$ both exceed the weak-coupling BCS limit, indicating moderate electron-phonon coupling. Compared to the structurally analogous compound ${\mathrm{Sc}}_6{\mathrm{RuTe}}_2$ ($T_{\text{c}}^{\text{zero}}\sim$ 1.9 K), the $T_{\mathrm{c}}$ of ${\mathrm{Sc}}_6{\mathrm{RuSb}}_2$ is nearly doubled. First-principles calculations show that substituting Sb for Te reduces the valence electron count, shifting the Fermi level from a density-of-states (DOS) valley toward a nearby DOS peak, which enhances the DOS at the Fermi level and accounts for the increased $T_{\mathrm{c}}$.

Close

PrevNext

View figure in article

• Multiband superconductivity
• Superconductivity
• Superconductors