Magnetic Quantum Critical Point in YBa_2Cu_3O_{7-delta}? Resolving the Correlation Length Controversy

TL;DR

This paper uses mode coupling calculations to address the controversy over the correlation length near the magnetic quantum critical point in YBa_2Cu_3O_{7-delta}, potentially reconciling different experimental observations.

Contribution

It applies a mode coupling approach to explain the behavior of susceptibility and correlation length in hole-doped cuprates, clarifying the quantum critical point issue.

Findings

Discovery of a plateau in q-space susceptibility that inhibits divergence.

Reconciliation of neutron and NMR measurements of correlation length.

Insight into the proximity to a quantum critical point in cuprates.

Abstract

A mode coupling calculation which previously explained the Mott gap collapse induced in cuprates by electron doping is applied to the analogous problem of hole doping. A plateau in the q-space susceptibility is found to inhibit the rate of susceptibility divergence as T goes to 0. This effect could reconcile neutron and NMR measurements of the correlation length in this regime, and clarify the issue of proximity to a quantum critical point.