Tendencies toward nematic order in YBa2Cu3O6+x: Uniform distortion vs. incipient charge stripes

TL;DR

This paper investigates whether nematic order in underdoped YBCO arises from uniform lattice distortions or incipient charge stripes, using a phenomenological model to analyze neutron scattering data and propose further experimental tests.

Contribution

It extends a phenomenological model to connect neutron scattering signatures with charge stripe tendencies, clarifying the origin of nematic order in YBCO.

Findings

Magnetic incommensurability aligns with incipient stripe scenario

Temperature dependence explained by charge stripe fluctuations

Proposes experiments to differentiate between uniform distortion and stripe origins

Abstract

Recent neutron scattering and transport data obtained on underdoped YBCO, with strong signatures of rotation symmetry breaking at low temperatures, point toward electron-nematic order in the charge sector. Such order may originate from a uniform distortion with d-wave symmetry or as a precursor of a uni-directional stripe phase. Here, we discuss whether the neutron scattering data can be linked to incipient charge stripes. We employ and extend a phenomenological model for collective spin and charge fluctuations and analyze the resulting spin excitation spectrum under the influence of lattice anisotropies. Our results show that the experimentally observed temperature-dependent magnetic incommensurability is compatible with a scenario of incipient stripes, the temperature dependence being due to the temperature variation of both strength and correlation length of the charge stripes. Finally, we propose further experiments to distinguish the possible theoretical scenarios.