Fate of charge order in overdoped La-based cuprates
Karin von Arx, Qisi Wang, S. Mustafi, D. G. Mazzone, Masafumi Horio, Deepak John Mukkattukavil, E. Pomjakushina, Sunseng Pyon, T. Takayama, H. Takagi, T. Kurosawa, N. Momono, Masahiro Oda, N. B. Brookes, Davide Betto, Wenliang Zhang, Teguh Citra Asmara, Yi Tseng, Thorsten Schmitt, Yasmine Sassa, J. Chang
Abstract
Abstract In high-temperature cuprate superconductors, stripe order refers broadly to a coupled spin and charge modulation with a commensuration of eight and four lattice units, respectively. How this stripe order evolves across optimal doping remains a controversial question. Here we present a systematic resonant inelastic x-ray scattering study of weak charge correlations in La 2− x Sr x CuO 4 and La 1.8− x Eu 0.2 Sr x CuO 4 . Ultra high energy resolution experiments demonstrate the importance of the separation of inelastic and elastic scattering processes. Long-range temperature-dependent stripe order is only found below optimal doping. At higher doping, short-range temperature-independent correlations are present up to the highest doping measured. This transformation is distinct from and preempts the pseudogap critical doping. We argue that the doping and temperature-independent short-range correlations originate from unresolved electron–phonon coupling that broadly peaks at the stripe ordering vector. In La 2− x Sr x CuO 4 , long-range static stripe order vanishes around optimal doping and we discuss both quantum critical and crossover scenarios.