Interband nodal-region pairing and the antinodal pseudogap in hole doped cuprates

TL;DR

This paper develops a multiband model for hole-doped cuprates, explaining the coexistence of nodal superconducting gaps and the antinodal pseudogap through doping-dependent electronic spectrum evolution.

Contribution

It introduces a new multiband framework that captures the doping evolution of the electronic spectrum and the distinct roles of nodal and antinodal regions in cuprate superconductivity.

Findings

The model reproduces the doping dependence of the superconducting gaps.

It explains the pseudogap as a band structure effect.

Qualitative agreement with experimental observations across doping levels.

Abstract

Recent experimental findings show that the pairing interaction in hole-doped cuprates resides in the nodal (FS arcs) region accompanied by the separate antinodal pseudogap. A corresponding multiband model of cuprate superconductivity is developed. It is based on the electronic spectrum evolving with doping and extends authors earlier approaches. The leading pair-transfer interaction is supposed between the itinerant (mainly oxygen) band and a nodal defect (polaron) band created by doping. These components are overlapping. The defect subband created in the antinodal region of the momentum space does not participate in the pairing by symmetry arguments. A supposed bare gap separating it from the itinerant band top disappears with extended doping. The corresponding antinodal pseudogap appears as a perturbative band structure effect. The low energy excitation spectrum treated in the mean-field approximation includes two nodal superconducting gaps and one pseudogap. The behaviour of these gaps and of other pairing characteristics agree qualitatively with the observations on the whole doping scale.