Oxygen-stripes in La0.5Ca0.5MnO3 from ab initio calculations

TL;DR

This study uses ab initio calculations to reveal that La0.5Ca0.5MnO3 exhibits a complex charge-density wave of oxygen holes coupled with magnetic and orbital order, aligning with experimental observations.

Contribution

It introduces a detailed ab initio analysis showing oxygen holes and complex charge order in La0.5Ca0.5MnO3, beyond simple Mn d-level models.

Findings

Charge-ordering stripe-like ground state identified

Agreement with neutron and x-ray diffraction data

Complex structure involves oxygen holes and charge-density wave

Abstract

We investigate the electronic, magnetic and orbital properties of La0.5Ca0.5MnO3 perovskite by means of an ab initio electronic structure calculation within the Hartree-Fock approximation. Using the experimental crystal structure reported by Radaelli et al. [Phys. Rev B 55, 3015 (1997)], we find a charge-ordering stripe-like ground state. The periodicity of the stripes, and the insulating CE-type magnetic structure are in agreement with neutron x-ray and electron diffraction experiments. However, the detailed structure is more complex than that envisaged by simple models of charge and orbital order on Mn d-levels alone, and is better described as a charge-density wave of oxygen holes, coupled to the Mn spin/orbital order.