Neutron Scattering and $d$-Wave Symmetry in the Cuprates

TL;DR

This paper demonstrates that neutron scattering data in cuprates support a d-wave symmetry of the superconducting order parameter, using realistic calculations that align with experimental observations and predict differences in related materials.

Contribution

The paper provides concrete calculations of neutron scattering structure factors that confirm d-wave symmetry in YBa2Cu3O7 and predict different q-structures in La2Sr0.15Cu1.85O4 due to fermiology.

Findings

Neutron scattering data are consistent with d-wave symmetry in YBa2Cu3O7.

Predicted q-structure differences in La2Sr0.15Cu1.85O4 due to fermiology.

Calculations include realistic Fermi surface effects and align with normal state data.

Abstract

In this comment we demonstrate that the general conjectures of Fong $et~ al$ on their ${\rm YBa_2Cu_3O_7}$ neutron experiments are realized in concrete calculations of the neutron scattering structure factor $S({\bf q} , \omega )$ in this material. We make predictions for similar experiments in ${\rm La_2Sr_{0.15}Cu_{1.85}O_4}$, which yield a different q-structure due to the different fermiology. Our calculations address both the frequency and wave-vector dependence of the data and (1) include realistic Fermi surface effects (2) are compatible with the normal state data and (3) demonstrate the consistency of a $d$-wave order parameter, in ${\rm YBa_2Cu_3O_7}$ although they appear to be also compatible with an alternate symmetry specific to the orthorhombic bi-layer system.