Excitation Gap in the Normal State of Underdoped Bi 2 Sr 2 CaCu 2 O 8+ δ
- 19 July 1996
- journal article
- research article
- Published by American Association for the Advancement of Science (AAAS) in Science
- Vol. 273 (5273) , 325-329
- https://doi.org/10.1126/science.273.5273.325
Abstract
Angle-resolved photoemission experiments reveal evidence of an energy gap in the normal state excitation spectrum of the cuprate superconductor Bi2Sr2CaCu2O8+δ. This gap exists only in underdoped samples and closes around the doping level at which the superconducting transition temperature Tc is a maximum. The momentum dependence and magnitude of the gap closely resemble those of the dx2−y2 gap observed in the superconducting state. This observation is consistent with results from several other experimental techniques, which also indicate the presence of a gap in the normal state. Some possible theoretical explanations for this effect are reviewed.Keywords
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