Evidence for an energy scale for quasiparticle dispersion in Bi2Sr2CaCu2O8
Quasiparticle dispersion in Bi2Sr2CaCu2O8 is investigated with improved angular resolution as a function of temperature and doping. Unlike the linear dispersion predicted by the band calculation, the data show a sharp break in dispersion at 50+/-15 meV binding energy where the velocity changes by a factor of 2 or more. This change provides an energy scale in the quasiparticle self-energy. This break in dispersion is evident at and away from the d-wave node line, but the magnitude of the dispersion change decreases with temperature and with increasing doping.
Bogdanov
PV
Department of Physics, Applied Physics and Stanford Synchrotron Radiation Laboratory, Stanford University, Stanford, California 94305, USA.
Lanzara
A
Kellar
SA
Zhou
XJ
Lu
ED
Zheng
WJ
Gu
G
Shimoyama
J
Kishio
K
Ikeda
H
Yoshizaki
R
Hussain
Z
Shen
ZX