Anomalous lattice relaxation dynamics in optimally doped La_2−𝑥⁢Sr_𝑥⁢CuO₄

The atomic lattice plays a critical role in the emergence of high-𝑇_𝑐 superconductivity in cuprates. While the dynamics associated with electron-lattice coupling typically unfold on picosecond-to-femtosecond timescales, we present an x-ray photon correlation spectroscopy investigation on an optimally doped La-based cuprate that reveals a strong response of kilosecond-scale lattice relaxation dynamics to the superconducting state. Notably, an anomaly emerges around 𝑇_𝑐: upon cooling into the superconducting state, the average atomic relaxation lifetime decreases, i.e., dynamics accelerate. This indicates a significant change in the local disorder-induced strain field dynamics at the superconducting transition, highlighting a remarkable coupling between superconductivity and the lattice on quasistatic timescales.. Authors: Petsch, A. N. [SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States); Stanford Univ., CA (United States)]; Shen, Lingjia [SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States); Lund Univ. (Sweden)] (ORCID:0000000221212585); Porter, Z. [SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States); Stanford Univ., CA (United States)] (ORCID:0000000229459558); Alshemi, A. [Lund Univ. (Sweden)] (ORCID:0000000302715299); Stellhorn, A. [Lund Univ. (Sweden)] (ORCID:000000032868657X). DOE Contract: AC02-76SF00515