Nature of the Electronic Excitations near the Brillouin Zone Boundary of Bi${}_2$Sr${}_2$CaCu${}_2$O${}_{8+\delta }$

Abstract

Based on angle resolved photoemission spectra measured on different systems at different dopings, momenta and photon energies, we show that the anomalously large spectral linewidth in the $(\pi ,0)$ region of optimal doped and underdoped Bi${}_2$Sr${}_2$CaCu${}_2$O${}_{8+\delta }$ has significant contributions from the bilayer splitting, and that the scattering rate in this region is considerably smaller than previously estimated. This new picture of the electronic excitation near $(\pi ,0)$ puts additional experimental constraints on various microscopic theories and data analysis.

5 pages, 4 figures