*4PO4-20 Photon Energy Dependence on ARPES spectra of Ca2CuO2Cl2
Filip Ronning 1, Changyoung Kim 2, D.H. Lu 2, N.P. Armitage 2, A. Damascelli 2, D.L. Feng 2, K.M. Shen 2, Zhi-Xun Shen 2, L.L. Miller 3, and Y.J. Kim 4. 1 Dept. of Physics, Stanford University, Stanford, CA 94305. 2 Dept. of Physics, Applid Physics, and SSRL, Stanford University, Stanford, CA 94305. 3 Dept. of Physics, Iowa State University, Ames, IA 50011. 4 M.I.T., Cambridge, MA 02139.
Presenting Author: F. Ronning
We report ARPES measurements on a parent high temperature superconducting compound, Ca2CuO2Cl2. Specifically, we examine the relative n(k) and the dispersion of the low energy feature as a function of photon energy in order to better understand the spectral features seen in Bi2Sr2CaCu2O8+d samples. We find, independent of photon energy, that the spectral weight in the insulator drops as one approximately crosses the antiferromagnetic zone boundary, and that the d-wave-like dispersion along the antiferromagnetic zone boundary shows a rounding close to the node region.
4PO4-21 Neutron (p,p) Resonance in Underdoped Bi2212 and its Relation to the Electronic Spectra as Measured by ARPES
Joel Mesot 1, Martin Boehm 1,3, Naoto Metoki 2, Arno Hiess 3,
and Kazuo Kadowaki 4. 1 Laboratory for Neutron Scattering, ETH-Zurich
and Paul Scherrer Institute, 5232 Villigen, Switzerland. 2 Advanced
Science Res. Center, Japan Atomic Energy Res. Inst., Tokai, Ibaraki 319-1195.
3 Insitut Laue Langevin BP 156X, F-38042 Grenoble, France. 4 Institute
of Materials Science, University of Tsukuba, Ibaraki 305, Japan.
Presenting author: Joel Mesot The main goal of this study is to understand, at a quantitative level,
the relation existing between the (p,p) resonance mode observed by
Inelastic Neutron Scattering (INS) and the electronic spectra, in the
superconducting state, measured by Angle Resolved Photoemission Spectroscopy
(ARPES). While all ARPES data on the doping dependence of the spectral
function have been obtained for Bi2212, the only INS data available on the
doping dependence of the neutron resonance have been reported for Y123.
We report, for the first time, INS measurement obtained for
underdoped (Tc=70K) Bi2212 single crystals. Below the critical
temperature a
pronounced resonance centered at Q=(p,p) and E=34 meV appears in
the neutron spectra. Its temperature and Q dependence clearly indicate
the magnetic origin of this resonance.
Furthermore, we compare our INS data with ARPES data obtained
on single crystals of the same origin. It is found that the energy of the
neutron resonance is in good agreement with the mode inferred from the
electronic spectra, thus indicating that the resonance/mode is intimately
connected to the pairing mechanism.
4PO4-23 Evidence for any energy scale for quasiparticle dispersion in Bi2Sr2CaCu2O8
A. Lanzara 1, 2, P.V. Bogdanov 1, 2, S.A. Kellar 1, X.J. Zhou 1, W. Zheng 1, E.D. Lu 2, G. Gu 3, K. Kishio 4, J. –I. Shimoyama 4, Z. Hussain 2, and Z.X. Shen 1. 1 Department of Physics, Applied Physics and Stanford Synchrotron Radiation Laboratory, Stanford University, Stanford, CA 94305, USA. 2 Advanced-Light Source, Lawrence Berkeley National Lab, Berkeley, Ca 94720. 3 School of Physics, University of New South Sales, P.O. Box 1, Kensington, NSW, Australia 2033. 4 Department of Applied Chemistry, University of Tokyo, Japan.
Presenting author: A. Lanzara
We present high-resolution ARPES data from Bi2Sr2CaCu2O8 superconductors as a function of doping and temperature. A clear break in the quasiparticle dispersion near 50-10 meV binding energy has been observed, resulting in a change of the quasiparticle velocity up to a factor of two or more. This break is present at various points of the momentum space and the magnitude of the dispersion change decreases with temperature and with increasing doping. This change provides an energy scale in the quasiparticle self-energy and may constitutes an important part of the puzzle related to high Tc superconductivity.