The topology of the Fermi surface of Bi2Sr2CaCu2O8-δ from angle resolved photoemission

We present a study of the topology of the normal state Fermi surface (FS) of the high T-c superconductor Bi2Sr2CaCu2O8-delta (Bi2212) using angle-resolved photoemission. We present FS mapping experiments, recorded using unpolarised radiation with high (E,k) resolution, and an extremely dense sampling of k-space. In addition, synchrotron radiation-based ARPES has been used to prove the energy independence of the FS as seen by photoemission. We resolve the current controversy regarding the normal state FS in Bi2212. The true picture is simple, self-consistent and robust: the FS is holelike, with the form of rounded tubes centred on the corners of the Brillouin zone. Two further types of features are also clearly observed: shadow FSs, and diffraction replicas of the main FS caused by passage of the photoelectrons through the modulated Bi-O planes.