Investigating quasi-circular dynamic charge order correlations through a phase transition in the cuprate LNSCO

The presence of static charge order (CO) and dynamic charge order correlations is pervasive throughout the cuprate family [1]. Recently, by using phonon softening as a marker for the presence of dynamic CO correlations in RIXS measurements as a function of azimuthal angle ϕ, we reported a manifold of quasi-circular dynamic correlations (QCDCs) in the qx-qy plane of Bi2Sr2CaCu2O8+x (Bi-2212) [2]. Using the same methodology, we seek to explore the QCDCs in La1.6-xNd0.4SrxCuO4 (LNSCO, x=0.125) both through the q-mapping that proved insightful in Bi-2212 and to study the temperature dependence of the QCDCs (of particular interest in LNSCO due its sharp structural phase transition). We propose to track how the softening of the bond stretching phonon in LNSCO evolves as a function of temperature around q=|q|=qCO, the preliminary results of which are already promising.