Transport properties and an electronic phase diagram of Bi-based high-T_c superconductors

This paper describes the electronic phase diagram of Bi-based high-T_c superconductors (Bi₂Sr₂CaCU₂O_{8 + δ}) revealed by their transport properties. Because the normal state properties of high-T_c cuprates are hard to understand within the Fermi-liquid picture, which provides the basis for the BCS theory, studies on the normal state properties are becoming very important. We explored the underdoped properties of Bi₂Sr₂CaCu₂O_{8 + δ}J by growing high-quality single crystals and controlling their oxygen content precisely. Based on the results, we propose a new electronic phase diagram of the pseudogap state for high-T_c cuprates.