Superconductivity versus structural phase transition in the closely related Bi${}_2$Rh${}_{3.5}$S${}_2$ and Bi${}_2$Rh${}_3$S${}_2$

Abstract

Single crystals of Bi${}_2$Rh${}_3$S${}_2$ and Bi${}_2$Rh${}_{3.5}$S${}_2$ were synthesized by solution growth and the crystal structures, thermodynamic and transport properties of both compounds were studied. In the case of Bi${}_2$Rh${}_3$S${}_2$, a structural first-order transition at around 165 K is identified by single crystal diffraction experiments, with clear signatures visible in resistivity, magnetization and specific heat data. No superconducting transition for Bi${}_2$Rh${}_3$S${}_2$ was observed down to 0.5 K. In contrast, no structural phase transition at high temperature was observed for Bi${}_2$Rh${}_{3.5}$S${}_2$, however bulk superconductivity with a critical temperature, $T_c\approx$ 1.7 K was observed. The Sommerfeld coefficient $\gamma$\ and the Debye temperature(${\Theta }_{\text{D}}$) were found to be 9.4 mJ mol${}^{-1}$ K${}^{-2}$ and 209 K respectively for Bi${}_2$Rh${}_3$S${}_2$, and 22 mJ mol${}^{-1}$ K${}^{-2}$ and 196 K respectively for Bi${}_2$Rh${}_{3.5}$S${}_2$. Study of the specific heat in the superconducting state of Bi${}_2$Rh${}_{3.5}$S${}_2$ suggests that Bi${}_2$Rh${}_{3.5}$S${}_2$ is a weakly coupled, BCS superconductor.

8 pages, 11 figures

References in corpus (2)

• Pressure-induced superconductivity in single crystal CaFe2As2
• Superconductivity of La${}_3$Co${}_4$Sn${}_{13}$ and La${}_3$Rh${}_4$Sn${}_{13}$: A comparative study

Cited by in corpus (1)

• Optical spectroscopy and ultrafast pump-probe study on Bi${}_2$Rh${}_3$Se${}_2$: evidence for charge-density-wave order formation