Differentiation of Site-Specific Symmetry Breaking Orders in Y$_{1-x}$Pr$_x$Ba$_2$Cu$_3$O$_{6+y}$

Abstract: 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${1-x}$Pr$_x$Ba$_2$Cu$_3$O${6+y}$ hosts two distinct orderings with almost identical translational symmetry breaking. Only when applying site-sensitive resonant elastic x-ray scattering (REXS), charge ordering can be conclusively differentiated from a super-lattice structure. These two orderings occur with almost the same in-plane symmetry but manifest at different atomic sites and display different temperature dependence. Differentiating these orders provides an important clue to the anomalous behavior of PrBa$_2$Cu$_3$O$_7$ within the 123-series of high-temperature superconductors. We conclude that the symmetry breaking at the Pr-site is unfavorable for superconducting pairing.