Theory of the Spin Gap in High Temperature Superconductors

TL;DR

This paper proposes a theory explaining the spin gap in underdoped cuprates through interplane pairing enhanced by magnetic correlations, analyzing two models of in-plane antiferromagnetic interactions.

Contribution

It introduces a pairing theory based on magnetic correlations in spin liquids, considering two models and estimating the pairing temperature and gap structure.

Findings

Interplane pairing explains the spin gap phenomenon.

Estimated pairing temperature $T_s$ aligns with experimental observations.

Different in-plane magnetic correlation models affect the gap's angular dependence.

Abstract

We analyze pairing in two dimensional spin liquids. We argue that interplane pairing enhanced by magnetic correlations is the most plausible explanation of the spin gap phenomenon observed in underdoped cuprates. The details of the pairing theory depend on the in-plane antiferromagnetic correlations. We consider two models: $2p_F$ correlations induced by a strong gauge field interaction and undamped spin waves. We estimate the pairing temperature $T_s$ and the angular dependence of the gap function and discuss physical consequences.