Giant Nonlinear Electron-lattice Interaction in Cuprate Superconductors, and Origin of the Pseudogap

TL;DR

This paper reveals a strong nonlinear coupling between electrons and oxygen vibrations in cuprates, explaining the pseudogap phase and its relation to symmetry breaking from first principles, with implications for superconductivity.

Contribution

It introduces a first-principles model linking electron-oxygen coupling to the pseudogap and symmetry breaking in cuprates, advancing understanding of high-temperature superconductivity.

Findings

Strong nonlinear electron-oxygen coupling demonstrated via ab initio simulations.

Derived a C4 symmetry breaking and pseudogap phase diagram consistent with experiments.

Discussed implications for superconductivity and Fermi surface phenomena.

Abstract

The pseudogap is a key property of the cuprate superconductors, whose understanding should illuminate the pairing mechanism. Recent experimental data support a close connection between the pseudogap and an oxygen-driven C4 symmetry breaking within the CuO2 plane unit cell. Using ab initio Molecular Dynamics, we demonstrate the existence of a strong nonlinear electron-oxygen vibrator coupling in two cuprates. In a mean field approach applied to this coupling within a model Hamiltonian, we derive a C4 splitting/pseudogap phase diagram in agreement with experiment - providing an explanation for the pseudogap phenomenon from first principles. The implications for superconductivity and the Fermi surface arc effect are discussed.