Knight Shift vs Hole Concentration in Hg1201 and Hg1212

We studied the hole concentration dependences of 63Cu Knight shifts in single-CuO2-layer high-Tc cuprate superconductors HgBa2CuO4+δ and double-layer HgBa2CaCu2O6+δ. We found that the spin Knight shift at room temperature as a function of the hole concentration in the single-layer superconductor is different from that in the double-layer superconductor. Two type relations between the spin Knight shift and the hole doping level serve to estimate the individual hole concentrations of the non-equivalent CuO2 planes in a unit cell.