Evidence for abrupt change in dispersion and scattering rate of quasiparticles in Bi2Sr2CaCu2O8

Abstract We report high-resolution ARPES data from Bi 2 Sr 2 CaCu 2 O 8 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 doping.