Extended Moment Formation and Second Neighbor Coupling in LiCuO2
Ruben Weht and W. E. Pickett, Phys. Rev. Lett. 81, Sept 21 (1998)

The Cu-O edge-sharing compound Li2CuO2, whose ferromagnetic chains are antialigned, is found from local spin density calculations to display several surprising characteristics: (1) the ordered moment/f.u. of 0.92 muB is the largest for any low dimensional cuprate system, in agreement with experiment, (2) 40% of this moment lies on the neighboring O ions, making it the largest oxygen moment yet reported, and (3) the second neighbors couplings are larger than nearest neighbors couplings. All of these phenomena arise naturally due to a well defined effective dyz type orbital that includes very strong O psigma character. We interpret the large moment as surviving reduction by quantum fluctuations due to extension caused by the d-p hybridization.