Impact of Intrinsic Disorder on Superconductivity in Cuprates

Theoretical analyses of superconductivity typically assume a compositionally-uniform lattice. In cuprates, the dopant ions, such as Sr²⁺ for La³⁺ in La_2-xSr_xCuO₄ (LSCO), are randomly distributed in the lattice and are poorly screened, resulting in an inhomogeneous charge landscape that is commonly ignored by theory [1]. As a consequence of the inhomogeneity, features such as spin and charge stripe correlations evolve with doping through a percolation transition, rather than a quantum critical point [2]. In underdoped cuprates, the presence of charge disorder can help to explain why the <i>d</i>-wave superconducting gap does not appear to be coherent at the gap maximum [1,3]. In overdoped LSCO, the charge inhomogeneity leads to multiple superconducting transitions [4] and appears to underlie the strange-metal behavior in the normal-state resistivity [2]. I will discuss the evidence behind these claims.<br/><br/>Work at Brookhaven is supported by the Office of Basic Energy Sciences, Materials Sciences and Engineering Division, U.S. Department of Energy, through Contract No. DE-SC0012704.<br/><br/>1. J. M. Tranquada, Adv. Phys. <b>69</b>, 437 (2020).<br/>2. P. M. Lozano <i>et al</i>., arXiv:2307.13740 (2023).<br/>3. Y. Li <i>et al</i>., Phys. Rev. B <b>98</b>, 224508 (2018).<br/>4. Y. Li <i>et al</i>., Phys. Rev. B <b>106</b>, 224515 (2022).