Quasi-1D dynamics and nematic phases in the 2D Emery model

TL;DR

This paper demonstrates that in a strong-coupling limit, the 2D Emery model exhibits quasi-one-dimensional electron dynamics and stable nematic phases that break lattice symmetry, providing exact insights into high-temperature superconductor behavior.

Contribution

It reveals that strong Coulomb interactions induce quasi-1D behavior and stabilize nematic phases in the Emery model, offering new exact results for high-temperature superconductor physics.

Findings

Electron dynamics become strictly one-dimensional under strong coupling.

A nematic phase is stable at low temperatures and strong interactions.

Asymptotically exact results are derived for the electronic structure.

Abstract

We consider the Emery model of a Cu-O plane of the high temperature superconductors. We show that in a strong-coupling limit, with strong Coulomb repulsions between electrons on nearest-neighbor O sites, the electron-dynamics is strictly one dimensional, and consequently a number of asymptotically exact results can be obtained concerning the electronic structure. In particular, we show that a nematic phase, which spontaneously breaks the point- group symmetry of the square lattice, is stable at low enough temperatures and strong enough coupling.