Orbital Order, Superconductivity, Pseudogap and Spectral Weight in High-Tc Cuprates

TL;DR

This paper presents a microscopic model explaining superconductivity and pseudogap phenomena in high-Tc cuprates, linking orbital arrangements to spectral features and phase behaviors, with results aligning well with experimental observations.

Contribution

It introduces a novel microscopic mechanism based on oxygen orbital arrangements that accounts for superconductivity and pseudogap features in high-Tc cuprates, supported by spectral density calculations.

Findings

Attractive hole interaction arises from magnetic interactions with copper ions.

Spectral density exhibits two peaks with a pseudogap, consistent with d-wave symmetry.

Model results match experimental spectral data across phases.

Abstract

After providing a brief genealogy of our recently proposed model for High-Tc cuprates, we investigate the details of the microscopic mechanism that produces an attractive interaction between neighboring holes. We show that a peculiar arrangement of the $p_x$ and $p_y$ oxygen orbitals makes the mutual magnetic interaction of the holes with the localized copper ions to produce a net attractive interaction between themselves, which is responsible for the emergence of a superconducting phase. We also study the connection existing between the proposed pseudogap order parameter and the spectral density. We show that the occurrence of two sharp peaks in the latter, between which the density of states suffers a depletion is a direct consequence of the d-wave character of the pseudogap order parameter dependence on $\mathbf{k}$, which breaks the 90$^\circ$-rotation symmetry of the oxygen lattices. The peak separation in the spectral density works effectively as an overall pseudogap order parameter for the cuprates. We explicitly calculate the spectral density in the strange metal and pseudogap phases of Bi2212, at different temperatures, and show that our results compare very well with the experimental data.