Lightly doped [Formula presented] in the so-called insulating hase has been studied by angle-resolved photoemission spectroscopy. We have observed that a quasiparticle (QP) peak crosses the Fermi level in the node direction of the [Formula presented]-wave superconducting gap, forming an arc of Fermi surface, which explains the metallic behavior at high temperatures of the lightly doped materials. The QP spectral weight of the arc smoothly increases with hole doping, which we attribute to the [Formula presented] behavior of the carrier number in the underdoped and lightly doped regions.
ASJC Scopus subject areas
- Physics and Astronomy(all)