Quantum critical points (QCPs), at which a second-order phase transition is continuously suppressed to zero temperature, are currently one of the central topics in solid-state physics^1,2. The strong interest emerges from observations of very unusual properties at QCPs such as the onset of unconventional superconductivity (SC)³. While QCPs found at the disappearance of magnetic order are quite common and intensively studied, a QCP that results from a structural transition is scarce and poorly investigated. Here, we report on the observation of a charge density wave (CDW) type of structural ordering in LuPt ₂In with a second-order transition at T_CDW = 490 K. Substituting Pd for Pt suppresses T_CDW continuously towards T = 0, leading to a QCP at 58% Pd substitution. We find a strong enhancement of bulk SC just at the QCP, pointing to a new type of interaction between CDW and SC.

量子临界点（QCPs）是二阶相变被连续抑制到零温度的位置，目前是固态物理学^1,2的中心主题之一。强烈的兴趣来自对QCP异常性质的观察，例如非常规超导电性（SC）^3的出现。虽然在磁序消失时发现的QCP相当普遍并且经过深入研究，但由于结构转变而产生的QCP却很少，而且研究也很少。在这里，我们报告观察到LuPt ₂ In中的电荷密度波（CDW）类型的结构有序，在T _CDW = 490 K处发生了二级过渡。用Pd代替Pt会抑制T _CDW连续地朝向T = 0，导致QCP的Pd取代率为58％。我们在QCP处发现了批量SC的强大增强，这表明CDW和SC之间存在一种新型的交互方式。