Single domain stripe order in a high-temperature superconductor La_2−xSr_xCuO₄

In the phase diagrams of lanthanum-based high-temperature cuprate superconductors, as the antiferromagnetism is suppressed, the stripe order phase appears in which the doped charges are concentrated along domain walls between antiferromagnetic regions [1]. However, one major hurdle in pinpointing the exact nature of this state has been the fact that these charge and spin density waves are always observed in a multidomain configuration, obscuring the direct determination of the intrinsic phase.

Uniaxial pressure can differentiate between different ground states, but the small ordered moment and background from pressure cells has up to now prevented such experiments. Here we tackle this challenge by designing a low-background uniaxial cell, optimizing the scattering experiment based on neutron-tracing simulations and making use of the unparalleled performance of the ThALES spectrometer at ILL [2].

We will present neutron scattering experiments, which demonstrate that the magnetic spin density wave order parameter is also uniaxial, the two density waves are coupled, and the fundamental electronic order is a single-domain stripe state [3].

[1] Tranquada et al., Nature 375, 561 (1995)

[2] Boehm et al., Neutron News 26, 18 (2015)

[3] Simutis et al., arXiv:2204.02304 (2022)