Broken translational and rotational symmetry via charge stripe order in underdoped YBCO

TL;DR

This study uses resonant x-ray scattering to demonstrate that charge order in underdoped YBCO is unidirectional stripe order, clarifying its microscopic nature and its competition with superconductivity.

Contribution

It provides direct experimental evidence for stripe-like charge order in YBCO, distinguishing it from checkerboard patterns and highlighting its role in cuprate physics.

Findings

Charge stripe order is observed in YBCO.

Charge order competes more strongly with superconductivity across stripes.

Charge modulations are intrinsically unidirectional.

Abstract

Following the early discovery of stripe-like order in La-based copper-oxide superconductors, charge ordering instabilities were observed in all cuprate families. However, it has proven difficult to distinguish between uni- (stripes) and bi-directional (checkerboard) charge order in Y- and Bi-based materials. Here we use resonant x-ray scattering (RXS) to measure the two-dimensional structure factor in YBCO, in reciprocal space. Our data reveal the presence of charge stripe order, i.e. locally unidirectional density waves, suggesting it as the true microscopic nature of charge modulations in cuprates. At the same time, we find that the well-established competition between charge order and superconductivity is stronger for charge correlations across than along the stripes, which provides additional evidence for the intrinsic unidirectional nature of the charge order.