Towards the issue of the origin of Fermi surface, pseudogaps and Fermi arcs in cuprate HTSCs

TL;DR

This paper proposes a new approach to understanding the electronic structure of cuprate high-temperature superconductors, explaining phenomena like Fermi arcs and pseudogaps through band dispersion and biexciton levels, and suggests a mechanism for superconducting pairing.

Contribution

It introduces a novel theoretical framework linking Fermi surface features and pseudogaps to biexciton levels and self-localization of doped carriers in cuprates.

Findings

Fermi surface is represented by an isoenergetic contour at a band section.

Biexciton levels act as acceptors, leading to hole carriers and chemical potential jumps.

The approach explains anomalies like Fermi arcs and pseudogaps in cuprates.

Abstract

Earlier we have proposed a new approach to the analysis of superconducting phase diagrams for cuprates and pnictides and have shown that the positions of superconducting domes on the diagrams can be predicted with high accuracy proceeding from only the crystal structure of a particular compound. The proposed approach uses the concept of the self-localization of doped carriers due to their formation of trion complexes that represent a bound state of the doped carrier and charge transfer excitons emerging under its influence. Here, as exemplified by cuprates, we show that the use of the proposed approach to the analysis of the transformation of an electronic structure with doping enables an explanation to a range of their anomalies: Fermi arcs, large and small pseudogaps etc. The basic conclusion is that the role of the Fermi surface in cuprates is played by an isoenergetic contour that emerges at the sectioning of the surface of a band dispersion by a dispersionless "biexciton" pair level. This level additionally plays the role of an acceptor to lead to the emergence of hole carriers on the isoenergetic contour and to a jump of the chemical potential. Based on the conducted consideration, we propose a possible mechanism of superconducting pairing genetically inherent in such a system.