Differentiation of site-specific symmetry breaking orders in Y_1-xPr_xBa₂Cu₃O_6+y

Solid matter is classified through symmetry of ordering phenomena. Experimentally, this approach is straightforward, except when distinct orderings occur with identical or almost identical symmetry breaking. Here we show that the cuprate system Y_1-xPr_xBa₂Cu₃O_6+y hosts two distinct orderings with almost identical translational symmetry breaking. Only when applying site-sensitive resonant elastic x-ray scattering, charge ordering can be conclusively differentiated from a super-lattice structure. These two orderings manifest at different atomic sites and display different temperature dependence. Differentiating these orders provides an important clue to the anomalous behavior of PrBa₂Cu₃O₇ within the 123-series of high-temperature superconductors. The superstructure symmetry breaking at the Pr-site should be included into future models of the unusual insulating ground state of PrBa₂Cu₃O₇.