Anisotropic spin and charge excitations in superconductors: signature of electronic nematic order

TL;DR

This paper investigates how electronic nematic order causes anisotropic spin and charge excitations in d-wave superconductors, revealing characteristic anisotropic peaks and collective modes linked to broken symmetry.

Contribution

It demonstrates the impact of electronic nematic order on spin and charge susceptibilities, highlighting anisotropic features in superconductors that align with recent experimental observations.

Findings

Anisotropic incommensurate peaks in spin susceptibility near ( extpi, extpi).

Presence of a collective charge mode with anisotropic amplitude.

Relevance to neutron scattering measurements in YBa2Cu3O6+x.

Abstract

We study spin and charge susceptibilities in the d-wave superconducting state whose underlying electronic dispersion is anisotropic due to the formation of the electronic nematic order. We show that the amplitude of the incommensurate peaks in the spin susceptibility near (\pi,\pi) reveals a pronounced anisotropy in the momentum space. The relevance of our findings to the magnetic scattering pattern observed in a recent neutron scattering measurement on untwinned YBa_2Cu_3O_{6+x} is discussed. In the charge channel, we identify a well-defined collective mode at small momentum transfer with strong anisotropic amplitude depending on the direction of momentum transfer, which is associated with the broken symmetry due to nematic ordering.