Nematic and spin-charge orders driven by hole-doping a charge-transfer insulator

TL;DR

This paper proposes a strong-coupling model explaining the emergence of various symmetry-breaking states in hole-doped cuprate superconductors through frustration of antiferromagnetic order, revealing a complex phase diagram.

Contribution

It introduces a multi-band variational model showing how diverse broken symmetry states can arise from hole doping in charge-transfer insulators.

Findings

Symmetry hierarchy includes spin and charge stripes, nematic order, and isotropic phases.

Multiple symmetry-breaking patterns compete with small energy differences.

The model reproduces a rich phase diagram consistent with experimental observations.

Abstract

Recent experimental discoveries have brought a diverse set of broken symmetry states to the center stage of research on cuprate superconductors. Here, we focus on a thematic understanding of the diverse phenomenology by exploring a strong-coupling mechanism of symmetry breaking driven by frustration of antiferromagnetic order. We achieve this through a variational study of a three-band model of the CuO$_2$ plane with Kondo-type exchange couplings between doped oxygen holes and classical copper spins. Two main findings from this strong-coupling multi-band perspective are 1) that the symmetry hierarchy of spin stripe, charge stripe, intra-unit-cell nematic order and isotropic phases are all accessible microscopically within the model, 2) many symmetry-breaking patterns compete with energy differences within a few meV per Cu atom to produce a rich phase diagram. These results indicate that the diverse phenomenology of broken-symmetry states in hole-doped antiferromagnetic charge-transfer insulators may indeed arise from hole-doped frustration of antiferromagnetism.