Superconductors with Hyperordered Structures

This section introduces superconductors with “hyperordered structures.” Recent rapid advancements in the physics and chemistry of superconductors have yielded diverse superconductors with intriguing and unique structures. Important superconducting materials were recently generated in two-dimensional (2D) layered compoundsTwo-dimensional (2D) layered compounds intercalated with various elements and molecules in which superconducting and insulating layers often coexist, that is, other ordered structures were created within the superconducting layers. Such a structure can be regarded as a “hyperordered structure.” This chapter outlines recent topical 2D layered compounds recognized as “hyperordered structures.” Moreover, other types of superconductors consisting of “hyperordered structures” are also introduced. For example, C60 is a typical hyperordered structure of carbon, that is, a carbon cluster. The superconductivity of materials consisting of clusters is also discussed in this chapter. The superconductivity in non-periodic structured materials, such as quasicrystals, which is considered as “superconductivity induced in an incomplete-ordered system (or non-periodic arrangement)” is introduced. Finally, the superconductivity discovered in graphite and graphene is described. In particular, the slight-twisted connection of two graphene sheets leads to the “Moiré super-lattice structure,” which explicitly modifies the electronic structure. Throughout this chapter, superconductivitySuperconductivity is discussed by considering the characteristic properties of “hyperordered structures.”