When sufficient numbers of holes are introduced into the two-dimensional CuO2 square lattice, dynamic magnetic correlations become incommensurate with underlying lattice in all previously investigated La_{ 2-x}A_xCu_{ 1-z}B_zO_{ 4+y} (A=Sr or Nd, B=Zn) including high T_C superconductors and insulators, and in bilayered superconducting YBa_2Cu_3O_{ 6.6} and Bi_2Sr_2CaCu_2O_8. Magnetic correlations also become incommensurate in structurally related La_2NiO_4 when doped with Sr or O. We report an exception to this so-far well established experimental "rule" in La_2Cu_{ 1-z}Li_{ z}O_4 in which magnetic correlations remain commensurate.
Categories: cond-mat.str-el cond-mat.supr-con