Nuclear Quadrupole Resonance Frequency in Multilayered Cuprates

抄録

The ⁶³Cu nuclear quadrupole resonance (NQR) frequency ν_Q in the multilayered cuprates is calculated in the cluster model by the exact diagonalization method. The charge imbalance between the outer CuO₂ plane (OP) with apical oxygen O_A and the inner plane (IP) without O_A in three-layered Tl₂Ba₂Ca₂Cu₃O₁₀ is estimated by comparing our results with the experimental ν_Q. In Tl-based cuprates with more than three layers, we predict a large enhancement of the splitting of ν_Q between OP and IP by taking into account the reduction in bond length between Cu and O_A and the resulting increase in charge transfer energy. Our results show that the NQR frequency is a useful quantity for estimating the charge imbalance in the multilayered cuprates.