We report the growth and physical properties of high-quality needle-shaped R⁢e3⁢G⁢e7 single crystal with various characterizations. It exhibits a gapped metal-insulator (MI)-like phase transition with evident Shubnikov–de Haas oscillation of low-𝑇 electrical resistivity. The superconducting phase diagram was revisited by measuring the electrical resistivity in a cubic anvil cell (CAC) under various hydrostatic pressures up to 12 GPa. Unlike the results of single crystals in a diamond anvil cell (DAC) and polycrystalline in CAC, the gapped MI-like phase transition of single-crystal R⁢e3⁢G⁢e7 evolves into three charge density wave (CDW)-like ones, which are reduced gradually by applied pressure and then collapse at several critical pressures; approaching the CDW-like quantum criticality, two distinct superconducting phases emerge and transit from one to another in a narrow pressure range; the significant increase in superconducting width indicates their strong competition. By combining density functional theory calculations, the origin of the melting MI-like transition caused by pressure and Ga doping, as well as the competitive CDW-like phase transitions and distinct superconductivity, are discussed.

中文翻译：

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静水压力下 aRe3Ge7 单晶中具有竞争力的多相变和不同的超导态


我们报道了具有各种表征的高质量针状 Re3Ge7 单晶的生长和物理性质。它表现出类似间隙金属绝缘体 （MI） 的相变，具有明显的低 T 电阻率 Shubnikov-de Haas 振荡。通过在高达 12 GPa 的各种静水压力下测量立方砧单元 （CAC） 中的电阻率，重新审视了超导相图。与金刚石砧电池 （DAC） 中的单晶和 CAC 中的多晶不同，单晶 Re3Ge7 的间隙 MI 样相变演变成三个电荷密度波 （CDW） 样相变，这些相变在施加压力下逐渐减小，然后在几个临界压力下坍缩;接近类似 CDW 的量子临界点，两个不同的超导相出现，并在狭窄的压力范围内从一个相转移到另一个相;超导宽度的显著增加表明它们具有很强的竞争能力。通过结合密度泛函理论计算，讨论了由压力和 Ga 掺杂引起的熔化 MI 样转变的起源，以及竞争性的 CDW 样相变和独特的超导性。