Correlation and disorder-enhanced nematic spin response in superconductors with weakly broken rotational symmetry

TL;DR

This paper investigates how weak lattice symmetry breaking and electronic correlations enhance nematic spin responses in underdoped cuprate superconductors, aligning with recent neutron scattering observations.

Contribution

It introduces a model combining d-wave superconductivity and Hubbard correlations to analyze spin susceptibility under broken rotational symmetry, revealing correlation-driven enhancement of nematic responses.

Findings

Correlation enhances spin response asymmetry near stripe order instability.

Impurities act as spin nematogens with C2 symmetry resonance states.

Disorder-averaged susceptibility remains C2 symmetric at low energies.

Abstract

Recent experimental and theoretical studies have highlighted the possible role of a electronic nematic liquid in underdoped cuprate superconductors. We calculate, within a model of d-wave superconductor with Hubbard correlations, the spin susceptibility in the case of a small explicitly broken rotational symmetry of the underlying lattice. We then exhibit how the induced spin response asymmetry is strongly enhanced by correlations as one approaches the instability to stripe order. In the disorder-induced stripe phase, impurities become spin nematogens with a C_2 symmetric impurity resonance state, and the disorder-averaged spin susceptibility remains only C_2 symmetric at low energies, similar to recent data from neutron scattering experiments on underdoped YBCO.