Stabilization of three-dimensional charge order in YBa$_2$Cu$_3$O$_{6+x}$ via epitaxial growth

TL;DR

This study demonstrates the stabilization of three-dimensional charge order in YBa2Cu3O6+x films grown epitaxially on SrTiO3, revealing the role of Cu sites in charge-reservoir layers and enabling new experiments without high magnetic fields.

Contribution

The paper shows 3D charge order in YBa2Cu3O6+x films grown epitaxially, highlighting the participation of Cu sites in charge-reservoir layers and eliminating the need for high magnetic fields.

Findings

3D charge order observed in epitaxial YBa2Cu3O6+x films.

Cu sites in charge-reservoir layers participate in charge order.

Charge order can be studied without high magnetic fields.

Abstract

Incommensurate charge order (CO) has been identified as the leading competitor of high-temperature superconductivity in all major families of layered copper oxides, but the perplexing variety of CO states in different cuprates has confounded investigations of its impact on the transport and thermodynamic properties. The three-dimensional (3D) CO observed in YBa$_2$Cu$_3$O$_{6+x}$ in high magnetic fields is of particular interest, because quantum transport measurements have revealed detailed information about the corresponding Fermi surface. Here we use resonant X-ray scattering to demonstrate 3D-CO in underdoped YBa$_2$Cu$_3$O$_{6+x}$ films grown epitaxially on SrTiO$_3$ in the absence of magnetic fields. The resonance profiles indicate that Cu sites in the charge-reservoir layers participate in the CO state, and thus efficiently transmit CO correlations between adjacent CuO$_2$ bilayer units. The results offer fresh perspectives for experiments elucidating the influence of 3D-CO on the electronic properties of cuprates without the need to apply high magnetic fields.