Formation of CuO$_2$ sublattices by suppression of interlattice correlations in tetragonal CuO

TL;DR

This study uses advanced computational methods to analyze the electronic and magnetic properties of tetragonal CuO, revealing insights into its sublattice formation, magnetic regimes, and implications for high-temperature superconductivity.

Contribution

It provides a formal justification for weak coupling assumptions and demonstrates that a single band Hubbard model captures the low-energy physics of t-CuO.

Findings

Identification of two magnetic regimes with distinct insulating states

Confirmation that a single band Hubbard model suffices for low-energy physics

Insights into how sublattice structure affects superconducting symmetry

Abstract

We investigate the tetragonal phase of the binary transition metal oxide CuO (t-CuO) within the context of cellular dynamical mean-field theory. Due to its strong antiferromagnetic correlations and simple structure, analysing the physics of t-CuO is of high interest as it may pave the way towards a more complete understanding of high temperature superconductivity in hole-doped antiferromagnets. In this work we give a formal justification for the weak coupling assumption that has previously been made for the interconnected sublattices within a single layer of t-CuO by studying the non-local self-energies of the system. We compute momentum-resolved spectral functions using a Matrix Product State (MPS)-based impurity solver directly on the real axis, which does not require any numerically ill-conditioned analytic continuation. The agreement with photoemission spectroscopy indicates that a single band Hubbard model is sufficient to capture the material's low energy physics. We perform calculations on a range of different temperatures, finding two magnetic regimes, for which we identify the driving mechanism behind their respective insulating state. Finally, we show that in the hole-doped regime the sublattice structure of t-CuO has interesting consequences on the symmetry of the superconducting state.