General Introduction

Layered compounds are an intriguing group of compounds that exhibit novel superconducting phenomena such as high-temperature superconductivity and triplet superconductivity. This thesis provides detailed information about the newly discovered superconductor \({\textit{R}_{2}\text {O}_{2}\text {Bi}}\) (R: rare earth) with unusual \({\text {Bi}^{2-}}\) square net, including its specific properties and the mechanism of superconductivity. Layered compounds with Bi \(^{-}\) square net have been extensively studied until today, leading to the emergence of the wide variety of quantum phenomena such as anisotropic Dirac fermion and Kondo lattice behavior, while superconducting Bi \(^{-}\) square net has not been realized yet. In contrast to the rich material group of Bi \(^{-}\) square net compounds, there are few reports about the synthesis of \({\text {Bi}^{2-}}\) square net compounds except for \({\textit{R}_{2}\text {O}_{2}\text {Bi}}\) in polycrystalline form. Chapter [1] serves as an introduction, discussing an overview of layered superconductors and properties of layered compounds with Bi \(^{-}\) square net.