The 63Cu nuclear quadrupole resonance (NQR) frequency, nu_q, in the multi-layered cuprates is calculated in the cluster model by the exact diagonalization method. The charge imbalance between the outer CuO_2 plane (OP) with apical oxygen (OA) and the inner plane (IP) without OA in three-layered Tl2223 is estimated by comparing our results with the experimental nu_q. In Tl-based cuprates with more than three layers, we predict a large enhancement of the splitting of nu_q between OP and IP by taking into account the reduction of bond length between Cu and OA and a resulting enhancement of the charge transfer energy. Our results show that the NQR frequency is a useful quantity to estimate the charge imbalance in the multi-layered cuprates.
@article{arxiv.0908.3721,
title = {Nuclear Quadrupole Resonance Frequency in Multi-Layered Cuprates},
author = {M. Mori and N. Afzal Shooshtary and T. Tohyama and S. Maekawa},
journal= {arXiv preprint arXiv:0908.3721},
year = {2009}
}