Incommensurate magnetic order and dynamics induced by spinless impurities in YBa$_2$Cu$_3$O$_{6.6}$

TL;DR

This study shows that 2% zinc impurities in underdoped YBa₂Cu₃O₆.₆ induce static magnetic order and alter spin excitations, revealing a universal impurity effect in layered copper oxide superconductors.

Contribution

It demonstrates how spinless impurities induce magnetic order and spectral redistribution, highlighting a universal behavior across layered cuprates.

Findings

Zn impurities induce static magnetic order.

Spectral weight shifts from 38 meV resonance to incommensurate excitations.

Behavior suggests a universal impurity effect in layered copper oxides.

Abstract

We report an inelastic-neutron-scattering and muon-spin-relaxation study of the effect of 2% spinless (Zn) impurities on the magnetic order and dynamics of YBa$_2$Cu$_3$O$_{6.6}$, an underdoped high-temperature superconductor that exhibits a prominent spin-pseudogap in its normal state. Zn substitution induces static magnetic order at low temperatures and triggers a large-scale spectral-weight redistribution from the magnetic resonant mode at 38 meV into uniaxial, incommensurate spin excitations with energies well below the spin-pseudogap. These observations indicate a competition between incommensurate magnetic order and superconductivity close to a quantum critical point. Comparison to prior data on La$_{2-x}$Sr$_x$CuO$_{4}$ suggests that this behavior is universal for the layered copper oxides and analogous to impurity-induced magnetic order in one-dimensional quantum magnets.