Pressure-induced superconductivity in monoclinic RhBi${}_2$

Abstract

RhBi${}_2$ is a polymorphic system that exhibits two distinct phases. RhBi${}_2$ in the triclinic phase has been identified as a weak topological insulator with a van Hove singularity point close to the Fermi energy. Thus, triclinic RhBi${}_2$ is expected to exhibit exotic quantum properties under strain or pressure. In this study, we report on the emergence of superconductivity in the monoclinic RhBi${}_2$ under external pressures. The electrical resistivity behavior of the monoclinic RhBi${}_2$ single crystal is studied at a wide range of applied external pressures up to 40 GPa. We observe a pressure-induced superconductivity with a dome-shaped dependence of the critical temperature on pressure at pressures above 10 GPa. A maximum critical temperature ($T_{\mathrm{c}}$) value of $T_{\mathrm{c}}$ = 5.1 K is reached at the pressure of 16.1 GPa. Furthermore, we performed detailed ab initio calculations to understand the electronic band structures of monoclinic RhBi${}_2$ under varying pressures. The combination of topology and pressure-induced superconductivity in the RhBi${}_2$ polymorphic system may provide us with a new promising material platform to investigate topological superconductivity.

6 pages, 5 figure