Constraints on the possible long-range orbital ordering in LaCoO3

A neutron powder diffraction measurement was performed to distinguish between the proposed monoclinic (I2/a) structure of LaCoO3, which is consistent with orbital ordering, and the rhombohedral (R3¯c) structure, which is inconsistent with orbital ordering. These two structures were differentiated through a measurement of a superlattice reflection with a d-spacing of approximately 4.43 Å which is only generated by I2/a. This reflection was not observed, and instead a restrictive upper bound was placed on its structure factor. The data is inconsistent with the monoclinic structure and suggests that there may be no long-range Jahn-Teller distortion in LaCoO3.