A pseudogap term in the magnetic response of the cuprate superconductors

TL;DR

This paper proposes a new magnetic response component in cuprate superconductors, explaining the pseudogap effects observed in NMR/NQR data but missing in neutron scattering measurements, advancing understanding of their magnetic properties.

Contribution

It introduces a novel contribution to the dynamic susceptibility in cuprates that accounts for pseudogap effects, bridging a gap between different experimental observations.

Findings

The new term explains pseudogap effects in NMR/NQR data.

It accounts for the missing pseudogap signals in INS measurements.

The contribution dominates nuclear relaxation at high temperatures.

Abstract

We combine neutron scattering (INS) and NMR/NQR nuclear spin lattice relaxation rate data to deduce the existence of a new contribution to the magnetic response (dynamic susceptibility) in cuprate superconductors. This contribution, which has yet to be observed with INS, is shown to embody the magnetic pseudogap effects. As such, it explains the long-standing puzzle of pseudogap effects missing from cuprate INS data, dominated by stripe fluctuations, for the dynamic susceptibility at low energies. For La_(1.86)Sr_(0.14)CuO_(4) and YBa_(2)Ba_(3)O_(6.5), the new term is the chief contributor to nuclear spin lattice relaxation at T >> T_(c).