paper

Metal-insulator-like transition, superconducting dome and topological electronic structure in Ga-doped Re $_{3}$ Ge $_{7}$

arXiv:2105.06028 · doi:10.1038/s41535-021-00372-z

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 $T_{c}$ 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.

11 pages, 7 figures

Metal-insulator-like transition, superconducting dome and topological electronic structure in Ga-doped Re3​Ge7​

Abstract

Metal-insulator-like transition, superconducting dome and topological electronic structure in Ga-doped Re $_{3}$ Ge $_{7}$