Loss of quasi-particle weight upon doping in cuprates

[doi:10.1038/nphys1763]
a, YBCO6.34 nodal dispersion and MDCs at E_F (±15 meV integration, shaded region), for light polarization parallel to Γ–S. b, YBCO7 MDCs for polarization along Γ–Y (note the strong polarization dependence). c, Evolution of k_F,N^B (down triangles) and k_F,N^AB (up triangles); below p≃0.15 the B–AB splitting vanishes and only one single k_F,N is detected (diamonds). d, Z_N as determined from the B–AB splitting with and the rescaled low-energy spectral-weight ratio . Also shown are spline guides-to-the-eye and the 2p/(p+1) relation (dashed red line). For the splitting-derived data, error bars are determined from the B–AB MDC fits when splitting is detected, and from the experimental resolutions otherwise; for the spectral weight ratio (SWR), they are calculated from the spread in SWR values for integration windows smaller than