Calculation of incommensurability and spin excitations of diagonal stripes in underdoped lanthanum cuprates

Based on the time-dependent Gutzwiller approximation we study the possibility that the diagonal incommensurate spin scattering in strongly underdoped lanthanum cuprates originates from antiferromagnetic domain walls (stripes). Calculation of the dynamic spin response for stripes in the diagonal phase yields the characteristic hour glass dispersion with the crossing of low-energy Goldstone and high-energy branches at a characteristic energy Ecross at the antiferromagnetic wave vector QAF. The high-energy part is close to the parent antiferromagnet. Our results suggest that inelastic neutron-scattering experiments on strongly underdoped lanthanum cuprates can be understood as due to a spatial mixture of bond-centered and site-centered stripe configurations with substantial disorder.