A Two Energy Gap Preformed-Pair Scenario For the Cuprates: Implications for Angle-Resolved Photoemission Spectroscopy

TL;DR

This paper presents a microscopic theory explaining the distinct temperature dependences of nodal and antinodal responses in cuprate pseudogaps, supporting a preformed pair scenario where the pseudogap arises from pairing correlations rather than competing orders.

Contribution

It introduces a fully microscopic T-matrix approach to describe pairing correlations in cuprates, linking the pseudogap to non-condensed and condensed pairs without relying on phenomenological fits.

Findings

Nodal and antinodal responses have different temperature dependences.

The theory aligns with various experiments in the moderately underdoped regime.

Supports the pseudogap as arising from pairing correlations, not competing orders.

Abstract

We show how, within a preformed pair scenario for the cuprate pseudogap, the nodal and antinodal responses in angle resolved photoemission spectroscopy necessarily have very different temperature $T$ dependences. We examine the behavior and the contrasting $T$ dependences for a range of temperatures both below and above $T_c$. Our calculations are based on a fully microscopic $T$-matrix approach for addressing pairing correlations in a regime where the attraction is stronger than BCS and the coherence length is anomalously short. Previously, the distinct nodal and anti-nodal responses have provided strong support for the "two-gap scenario" of the cuprates in which the pseudogap competes with superconductivity. Instead, our theory supports a picture in which the pseudogap derives from pairing correlations, identifying the two gap components with non-condensed and condensed pairs. It leads to reasonably good agreement with a range of different experiments in the moderately underdoped regime and we emphasize that here there is no explicit curve fitting. Ours is a microscopic rather than a phenomenological theory. We briefly address the more heavily underdoped regime in which the behavior is more complex.