In-plane charge modulation below T-c and charge-density-wave correlations in the chain layer in YBa2Cu3O7

Nuclear quadrupole resonance (NQR) measurements have been performed on Cu(2 ) plane sites and Cu(1) chain sires in fully doped YBa2Cu3O7 between 300 an d 4.2 K. The sharp increase of the Cu(1) NQR linewidth across the supercond ucting transition and the T dependence of the Cu(1) spin lattice relaxation rate confirm the existence of a charge-density-wave state (CDW) in the cha ins. The simultaneous broadening of the Cu(2) linewidth below T-c and the a nomalous T dependence of Cu(1) and Cu(2) NQR parameters indicate that these in-chain CDW correlations are strongly involved in the appearance of an in -plane charge modulated structure below T-c.