J.C. Campuzano, G. Jennings, M. Faiz, L. Beaulaigue, et al., "Fermi surfaces of YBa2Cu3O6.9 as seen by angle-resolved photoemission," Physical Review Letters, 64:2308-11, 1990.
Juan Carlos Campuzano (Argonne National Laboratory, Argonne, Ill.): "Originally, the high-temperature superconductors were expected to have an electronic structure akin to that of the ceramic insulators from whence they are derived. Insulators do not have free electrons to carry the current, and thus any electric field inside the material is not well screened, leading to a strong correlation between the motions of the electrons. If an insulator is doped, some charge carriers are injected. The expectation was that the volume of the Fermi surface, which describes the number of electrons per unit cell, would be very small. In turn, a theoretical description of these materials would have to account for the strong electron-electron correlation. This paper shows that the contrary is true: The volume of the ...
