INCOMMENSURATE MAGNETISM IN CUPRATE MATERIALS

In the low-doping region, an incommensurate magnetic phase is observed in La2-xSrxCuO4. By means of the composite-operator method we show th at the single-band two-dimensional Hubbard model reproduces with good accuracy the experimental situation. In the higher-doping region, wher e experiments are not available, the incommensurability is depressed o wing to the van Hove singularity near the Fermi level. By changing dop ing, the calculated incommensurability amplitude and the experimental critical temperature evolve in a similar way, suggesting a close relat ion between superconductivity and incommensurate magnetism.