Stripe-like correlations in the cuprates from oxygen NMR

TL;DR

This study uses oxygen NMR to reveal universal short-range stripe-like charge and spin correlations in cuprate superconductors, persisting across doping levels and possibly linked to quantum criticality and pseudogap phenomena.

Contribution

It provides new experimental evidence of stripe-like correlations in cuprates at high doping levels, highlighting their doping independence and potential role in quantum criticality.

Findings

Stripe-like correlations are nearly doping-independent up to x=0.30.

Correlations exhibit a phase slip near x=1/4 doping.

Correlations are generic to cuprates and resemble the average spin-charge relation.

Abstract

Nuclear magnetic resonance (NMR) of planar oxygen, with its family independent phenomenology, is ideally suited to probe the nature of the quantum matter of superconducting cuprates. Here, with new experiments on La$_{2-x}$Sr$_x$CuO$_4$, in particular also at high doping levels, we report on short-range stripe-like correlations between local charge and spin. Their amplitudes at room temperature are nearly independent of doping up to at least $x=0.30$, only their relative phase slips near $x=1/4$. Comparisons show the correlations to be generic to the cuprates. Despite the atomic scale length, the variations still resemble the average spin and charge relation, which is not expected from the otherwise simple, apparently metallic behavior, even far into the overdoped regime. Perhaps the phase slip is at the heart of a quantum critical point that demands pseudogap behavior towards lower doping levels in an otherwise strange metal.