On Nematicity and Charge Order in Superoxygenated La$_{2-x}$Sr$_x$CuO$_{4+y}$

Abstract: A nematic order in stripe-ordered cuprates was recently identified with (001) reflection at resonant energies associated with the in-plane states. However, whether this resonant reflection is ubiquitous among all 214 cuprates is still unknown. Here we report a Resonant soft X-ray Scattering (RXS) measurement on two La${2-x}$Sr$_x$CuO${4+y}$ crystals. Charge order was found in La$2$CuO${4+y}$ with a total hole concentration near 0.125/Cu but no measurable (001) peak at any resonance, while in a La${1.94}$Sr${0.06}$CuO$_{4+y}$ sample near 0.16/Cu a (001) peak resonant was identified to be consistent with the presence of LTT tilting. The lack of such a (001) peak in a compound with stripe-like charge order raises questions about nematicity and the origin of the scattering feature.