Metal-insulator-like transition, superconducting dome and topological electronic structure in Ga-doped Re${}_3$Ge${}_7$

Abstract

Superconductivity frequently appears by doping compounds that show a collective phase transition. So far, however, this has not been observed in topological materials. Here we report the discovery of superconductivity induced by Ga doping in orthorhombic Re${}_3$Ge${}_7$, which undergoes a second-order metal-insulator-like transition at $\sim$58 K and is predicted to have a nontrivial band topology. It is found that the substitution of Ga for Ge leads to hole doping in Re${}_3$Ge${}_{7-x}$Ga${}_x$. As a consequence, the phase transition is gradually suppressed and disappears above $x$ = 0.2. At this $x$ value, superconductivity emerges and $T_{\mathrm{c}}$ exhibits a dome-like doping dependence with a maximum value of 3.37 K at $x$ = 0.25. First-principles calculations suggest that the phase transition in Re${}_3$Ge${}_7$ is associated with an electronic instability driven by Fermi surface nesting and the nontrival band topology is preserved after Ga doping. Our results indicate that Ga-doped Re${}_3$Ge${}_7$ provides a rare opportunity to study the interplay between superconductivity and competing electronic states in a topologically nontrivial system.

arXiv comment11 pages, 7 figures

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Cited by in corpus (1)

• Superconductor--Insulator Transition in a non-Fermi Liquid