Interplay between atomic fluctuations and charge density waves in La\(_{2-x}\)Sr\(_{x}\)CuO\(_{4}\)

• Published in: arXiv.org 2023-04
• Main Authors: Shen, L, Esposito, V, Burdet, N G, Zhu, M, Petsch, A N, Croft, T P, Collins, S P, Ren, Z, Westermeier, F, Sprung, M, Hayden, S M, Turner, J J, Blackburn, E
• Format: Article
• Language: English
• Subjects: Charge density waves; Coherence; Crystal structure; Superconductors; Temperature dependence; X-ray scattering
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2304.12485

In the cuprate superconductors, the spatial coherence of the charge density wave (CDW) state grows rapidly below a characteristic temperature \(T_\mathrm{CDW}\), the nature of which is debated. We have combined a set of x-ray scattering techniques to study La\(_{1.88}\)Sr\(_{0.12}\)CuO\(_{4}\) (\(T_\mathrm{CDW}\)~\(\approx\)~80\,K) to shed light on this discussion. We observe the emergence of a crystal structure, which is consistent with the CDW modulation in symmetry, well above \(T_\mathrm{CDW}\). This global structural change also induces strong fluctuations of local atomic disorder in the intermediate temperature region. At \(T_\mathrm{CDW}\), the temperature dependence of this structure develops a kink, while the atomic disorder is minimized. We find that the atomic relaxation dynamics cross over from a cooperative to an incoherent response at \(T_\mathrm{CDW}\). These results reveal a rich interplay between the CDWs and atomic fluctuations of distinct spatio-temporal scales. For example, the CDW coherence is enhanced on quasi-elastic timescales by incoherent atomic relaxation.