X-ray and neutron diffuse scattering and Monte Carlo modeling of local structure in the cuprate HgBa₂CuO_4+δ

The cuprates are known as hosts of high-temperature superconductivity and of other correlated electronic phases, but the well-documented inhomogeneity of these materials is generally not considered. It was recently shown that, at a phenomenological level, much of the doping- and temperature-dependence of the seemingly complicated electronic phase diagram can be understood as rooted in a distribution of local environments [1]. Recent advances in X-ray and neutron diffuse scattering techniques have made it possible to determine correlated deviations from the average structure of materials. Here we report on X-ray and neutron diffuse scattering measurements of the structurally simple compound HgBa₂CuO_4+δ along with pair-distribution-function analysis of the data and reverse Monte Carlo refinement of the local structure. We will discuss the observed deviations from average structure and the implications of these results for the cuprates in general.

[1] D. Pelc et al., Sci. Adv. 5, eaau4538 (2019); Phys. Rev. B 102, 075114 (2020)