We calculated the nuclear spin-lattice relaxation rate 1/T1 for the D+iD superconducting state with impurities. We found that small amount of unitary impurities quickly produces the residual density of states inside the gap. As a result, the T-linear behavior in 1/T1 is observed at low temperatures. Our results show that the D+iD pairing symmetry of the superconducting state of Na0.35CoO2⋅yH2 O is compatible with recent 59Co 1/T1 experiments of several groups.
@article{arxiv.cond-mat/0307510,
title = {Nuclear spin-lattice relaxation rate in the D+iD superconducting state: implications for CoO superconductor},
author = {Yunkyu Bang and M. J. Graf and A. V. Balatsky},
journal= {arXiv preprint arXiv:cond-mat/0307510},
year = {2009}
}