title: Photoemission evidence for a remnant fermi surface and a d-wave-like dispersion in insulating Ca2CuO2Cl2
abstract: An angle-resolved photoemission study is reported on Ca2CuO2Cl2, a parent compound of high-Tc superconductors. Analysis of the electron occupation probability, n(k), from the spectra shows a steep drop in spectral intensity across a contour that is close to the Fermi surface predicted by the band calculation. This analysis reveals a Fermi surface remnant, even though Ca2CuO2Cl2 is a Mott insulator. The lowest energy peak exhibits a dispersion with approximately the &cjs3539;coskxa - coskya&cjs3539; form along this remnant Fermi surface. Together with the data from Dy-doped Bi2Sr2CaCu2O8+delta, these results suggest that this d-wave-like dispersion of the insulator is the underlying reason for the pseudo gap in the underdoped regime.
authors.affiliation: F. Ronning, C. Kim, D. L. Feng, A. G. Loeser, and Z.-X. Shen are with the Departments of Physics, Applied Physics, and Stanford Synchrotron Radiation Laboratory, Stanford, CA 94305, USA. D. S. Marshall is with the Departments of Physics, A.
authors.initials: F
authors.lastname: Ronning
authors.initials: C
authors.lastname: Kim
authors.initials: DL
authors.lastname: Feng
authors.initials: DS
authors.lastname: Marshall
authors.initials: AG
authors.lastname: Loeser
authors.initials: LL
authors.lastname: Miller
authors.initials: JN
authors.lastname: Eckstein
authors.initials: I
authors.lastname: Bozovic
authors.initials: Z
authors.lastname: Shen