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

Abstract

In this comment we demonstrate that the general conjectures of Fong $etal$ on their $\mathrm{YB}{\mathrm{a}}_2\mathrm{C}{\mathrm{u}}_3{\mathrm{O}}_7$ neutron experiments are realized in concrete calculations of the neutron scattering structure factor $S(\mathbf{q},\omega )$ in this material. We make predictions for similar experiments in $\mathrm{L}{\mathrm{a}}_2\mathrm{S}{\mathrm{r}}_{0.15}\mathrm{C}{\mathrm{u}}_{1.85}{\mathrm{O}}_4$, 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 $\mathrm{YB}{\mathrm{a}}_2\mathrm{C}{\mathrm{u}}_3{\mathrm{O}}_7$ although they appear to be also compatible with an alternate symmetry specific to the orthorhombic bi-layer system.

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