Theory of incommensurate magnetic correlations across the   insulator-superconductor transition in underdoped La_{2-x}Sr_xCuO_4
  The main feature in the elastic neutron scattering of La_{2-x}Sr_xCuO_4 is the existence of incommensurate peaks with positions that jump from 45 to 0 degrees at 5% doping. We show that the spiral state of the t-t'-t''-J model with realistic parameters describes this data perfectly. We explain why in the insulator the peak is at 45 degrees while it switches to 0 degrees precisely at the insulator-metal transition. The calculated positions of the peaks are in agreement with the data in both phases. 
Oleg P. Sushkov and Valeri N. Kotov