Coherent Quasiparticle Weight and Its Connection to High-Tc Superconductivity from Angle-Resolved Photoemission

We study the doping and temperature dependence of the single-particle coherent weight, z(A), for high-T-c superconductors Bi2Sr2CaCu2O8+x using angle-resolved photoemission. We find that at low temperatures the coherent weight z(A) at (pi ,0) is proportional to the carrier concentration x and that the temperature dependence of z(A) is similar to that of the c-axis superfluid density. We show that, for a wide range of carrier concentration, the superconducting transition temperature scales with the product of the low-temperature coherent weight and the maximum superconducting gap.