Spin-wave dispersion in half-doped LaSrNiO
arXiv:cond-mat/0609300 · doi:10.1103/PhysRevB.75.012414
Abstract
Recent neutron scattering measurements reveal spin and charge ordering in the half-doped nickelate, La Sr NiO. Many of the features of the magnetic excitations have been explained in terms of the spin waves of diagonal stripes with weak single-ion anisotropy. However, an optical mode dispersing away from the (π,π) point was not captured by this theory. We show here that this apparent optical mode is a natural consequence of stripe twinning in a diagonal stripe pattern with a magnetic coupling structure which is two-fold symmetric, i.e. one possessing the same spatial rotational symmetry as the ground state.
4 pages, 5 figures