Abstract
We report angle-resolved photoemission results on and oxygen depleted investigating the electronic structure changes above in materials with hole doping levels ranging from insulating to slightly overdoped. Near optimal hole doping, the Fermi surface is large and consistent with band calculations. In underdoped samples with of 60–70 K, portions of this Fermi surface are not seen. This change is related to the opening of an energy gap near above .
- Received 5 December 1995
DOI:https://doi.org/10.1103/PhysRevLett.76.4841
©1996 American Physical Society