High-temperature charge density wave correlations in La$_{1.875}$Ba$_{0.125}$CuO$_{4}$ without spin-charge locking

TL;DR

This study reveals that high-temperature charge density wave correlations in La$_{1.875}$Ba$_{0.125}$CuO$_{4}$ are independent of spin order, suggesting stripe order is stabilized by coupling of separate charge and spin density waves.

Contribution

It demonstrates that charge correlations at high temperature are decoupled from spin correlations, providing new insights into the nature of stripe order in cuprates.

Findings

High-temperature charge correlations are unlocked from spin wavevector.

Stripe order is stabilized by coupling of independent charge and spin density waves.

Charge correlations persist without spin order at high temperatures.

Abstract

Although all superconducting cuprates display charge-ordering tendencies, their low-temperature properties are distinct, impeding efforts to understand the phenomena within a single conceptual framework. While some systems exhibit stripes of charge and spin, with a locked periodicity, others host charge density waves (CDWs) without any obviously related spin order. Here we use resonant inelastic x-ray scattering (RIXS) to follow the evolution of charge correlations in the canonical stripe ordered cuprate La$_{1.875}$Ba$_{0.125}$CuO$_{4}$ (LBCO~$1/8$) across its ordering transition. We find that high-temperature charge correlations are unlocked from the wavevector of the spin correlations, signaling analogies to CDW phases in various other cuprates. This indicates that stripe order at low temperatures is stabilized by the coupling of otherwise independent charge and spin density waves, with important implications for the relation between charge and spin correlations in the cuprates.