Superconductivity in the spinels: Cu(Ir_{1-x}Pt_x)2Se4 and CuRh2S4

Spinels, which have formula AB2X4 and crystallise in the cubic space group, exhibit a rich landscape of structural, magnetic and electronic properties. However, superconducting compounds of this family have proven fairly elusive. Previous routes to reaching superconductivity is via substitution of the A ion, such as Cu-Zn substitution in CuIr2S4. The parent compound exhibits a metal-insulator transition, concomitant with a complex structural transition and a charge-ordered and spin-dimerised state. We propose to investigate an alternative pathway to superconductivity via substitution of the B ion. The systems we would like to study are prototypical examples of this and muons as sensitive local probes can give us important information about the electric, magnetic and superconducting properties, such as the pairing mechanism, which gives insights into the electro-structural coupling.

尖晶石（Spinels）的化学式为AB₂X₄，结晶于立方空间群，展现出丰富多样的结构、磁学与电学特性。然而，该家族的超导化合物始终难以获取。此前实现该类体系超导性的途径多通过取代A位离子，例如CuIr₂S₄中的Cu-Zn取代。其母相化合物会发生金属-绝缘体转变，同时伴随复杂的结构转变、电荷有序与自旋二聚化状态。我们提出通过取代B位离子，探索实现超导性的全新途径。本次拟研究的体系正是该研究方向的典型范例；而μ子（muons）作为高灵敏的局域探针，能够为我们提供有关电学、磁学与超导性质的关键信息——例如配对机制，这将有助于揭示电-结构耦合的内在关联。