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 d-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.

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.

1. J. M. Tranquada, Adv. Phys. 69, 437 (2020).
2. P. M. Lozano et al., arXiv:2307.13740 (2023).
3. Y. Li et al., Phys. Rev. B 98, 224508 (2018).
4. Y. Li et al., Phys. Rev. B 106, 224515 (2022).