Inhomogeneity of charge density wave order and quenched disorder in a high Tc superconductor

TL;DR

This study uses micro X-ray diffraction to map the nanoscale distribution of charge-density-wave domains and quenched disorder in a high-Tc superconductor, revealing complex spatial correlations that influence superconductivity.

Contribution

It provides the first detailed spatial imaging of charge-density-wave puddles and quenched disorder in a high-Tc superconductor, uncovering their non-random, anti-correlated distributions.

Findings

Charge-density-wave puddles have a fat-tailed size distribution.

Quenched disorder from oxygen interstitials is spatially anti-correlated with charge-density-wave domains.

The spatial landscape of superconductivity is shaped by complex emergent geometries.

Abstract

It has recently been established that the high temperature (high-Tc) superconducting state coexists with short-range charge-density-wave order and quenched disorder arising from dopants and strain. This complex, multiscale phase separation invites the development of theories of high temperature superconductivity that include complexity. The nature of the spatial interplay between charge and dopant order that provides a basis for nanoscale phase separation remains a key open question, because experiments have yet to probe the unknown spatial distribution at both the nanoscale and mescoscale (between atomic and macroscopic scale). Here we report micro X-ray diffraction imaging of the spatial distribution of both the charge-density-wave puddles (domains with only a few wavelengths) and quenched disorder in HgBa2CuO4+y, the single layer cuprate with the highest Tc, 95 kelvin. We found that the charge-density-wave puddles, like the steam bubbles in boiling water, have a fat-tailed size distribution that is typical of self-organization near a critical point. However, the quenched disorder, which arises from oxygen interstitials, has a distribution that is contrary to the usual assumed random, uncorrelated distribution. The interstitials-oxygen-rich domains are spatially anti-correlated with the charge-density-wave domains, leading to a complex emergent geometry of the spatial landscape for superconductivity.