We report the structural and superconducting evolution of the solid solution of ${\mathrm{Ir}}_{0.95-x}{\mathrm{Rh}}_x{\mathrm{Te}}_2$ ($0\le x\le 0.52$) and compare the results with those of analogous selenides. The structural analysis revealed that the unit cell unexpectedly expands and the separation of the Te${}_2$${}^{-2}$ dimer exhibits a maximal value of around $x=0.2$ with increasing Rh content. However, unlike the domed $T_c$ in ${\mathrm{Ir}}_{0.94-x}{\mathrm{Rh}}_x{\mathrm{Te}}_2$, the present system exhibits a monotonous decrease in $T_c$, which is independent of the instability of the Te${}_2$${}^{-2}$ dimer. As the analysis of resistivity and heat capacity, it is suggested that electron-electron/phonon correlation strength is a considerable factor leading to the different evolution of $T_c$ in the vicinity of the structural instability state of pyrite superconductors.

• Received 9 May 2013

DOI:https://doi.org/10.1103/PhysRevB.87.224504