We derive the theory of the quantum (zero temperature) superconductor to metal transition in disordered materials when the resistance of the normal metal near criticality is small compared to the quantum of resistivity. This can occur most readily in situations in which ``Anderson's theorem'' does not apply. We explicitly study the transition in superconductor-metal composites, in an s-wave superconducting film in the presence of a magnetic field, and in a low temperature disordered d-wave superconductor. Near the point of the transition, the distribution of the superconducting order parameter is highly inhomogeneous. To describe this situation we employ a procedure which is similar to that introduced by Mott for description of the temperature dependence of the variable range hopping conduction. As the system approaches the point of the transition from the metal to the superconductor, the conductivity of the system diverges, and the Wiedemann-Franz law is violated. In the case of d-wave (or other exotic) superconductors we predict the existence of (at least) two sequential transitions as a function of increasing disorder: a d-wave to s-wave, and then an s-wave to metal transition.
The strange metal Hall effect connects quantum criticality and superconductivity in an iron-based superconductor
许多非常规超导体表现出一组共同的异常电荷输运性质，将它们描述为“奇怪的金属”，这为存在描述它们的单一理论提供了希望。然而，奇怪的金属和超导性之间的模型无关的联系仍然难以捉摸。在这封信中，我们表明，非常规超导体BaFe $_2$（As $_{1-x}$ P $_x$）$_2$的霍尔效应包含一个奇怪的金属内的关联引起的异常贡献。这个项对磁场有着独特的依赖性，这使得我们能够跟踪它在掺杂温度相图上的行为，即使在超导圆顶下。这些测量表明，奇怪的金属霍尔组件从量子临界点发出，在零温度极限，超导临界温度成比例地衰减。这在量子临界性和超导性之间建立了一种清晰而新颖的联系，并表明类似的联系存在于其他奇怪的金属超导体中。
