Orbital symmetry of charge density wave order in La1.875Ba0.125CuO4 and YBa2Cu3O6.67

TL;DR

This study investigates the orbital symmetry of charge density wave order in two cuprate superconductors, revealing distinct symmetries in La1.875Ba0.125CuO4 and YBa2Cu3O6.67, which may influence their electronic properties and anomalies.

Contribution

It provides the first direct measurements of CDW orbital symmetry in LBCO and YBCO, showing contrasting s' and d symmetries and their directional dependence.

Findings

LBCO exhibits predominantly s' CDW orbital symmetry.

YBCO shows different CDW orbital symmetries along the a and b axes.

CDW orbital symmetry varies among cuprate families, affecting their properties.

Abstract

Recent theories of charge density wave (CDW) order in high temperature superconductors have predicted a primarily d CDW orbital symmetry. Here, we report on the orbital symmetry of CDW order in the canonical cuprate superconductors La1.875Ba0.125CuO4 (LBCO) and YBa2Cu3O6.67 (YBCO), using resonant soft x-ray scattering and a model mapped to the CDW orbital symmetry. From measurements sensitive to the O sublattice, we conclude that LBCO has predominantly s' CDW orbital symmetry, in contrast to the d orbital symmetry recently reported in other cuprates. Additionally, we show for YBCO that the CDW orbital symmetry differs along the a and b crystal axes and that these both differ from LBCO. This work highlights CDW orbital symmetry as an additional key property that distinguishes the different cuprate families. We discuss how the CDW symmetry may be related to the "1/8--anomaly" and to static spin ordering.