Doped Spin Ladder: Zhang-Rice Singlets or Rung-centred Holes?

TL;DR

This paper develops a charge transfer model for doped spin ladders in a specific cuprate compound, demonstrating the stability of Zhang-Rice singlets through Hartree-Fock calculations aligned with experimental data.

Contribution

It introduces a charge transfer model for doped spin ladders and shows the stability of Zhang-Rice singlets in this context, supported by theoretical and experimental agreement.

Findings

Zhang-Rice singlets are highly stable in the model.

The model aligns with recent x-ray absorption measurements.

Charge order influences the stability of doped holes.

Abstract

We formulate charge transfer model for a single doped spin ladder, relevant for the intrinsically doped plane of coupled spin ladders in Sr$_{3}$Ca$_{11}$Cu$_{24}$O$_{41}$. Assuming the presence of the experimentally observed charge order in the system we solve the model using Hartree-Fock approximation. Our results show the profound stability of the Zhang-Rice singlets with respect to other configurations of doped holes, in agreement with recent x-ray absorption measurements.