Magnetic polarons in doped 1D antiferromagnetic chain

TL;DR

This paper investigates the structure and interactions of magnetic polarons in a doped 1D antiferromagnetic chain, revealing two types of ferrons, their stability, and how impurity density influences their energy and interactions.

Contribution

It introduces a detailed analysis of ferron types, their stability conditions, and the attractive interactions between excited-state ferrons in doped 1D antiferromagnetic chains.

Findings

Two ferron types exist with distinct spin distortions.

Ground state ferrons are localized near impurities.

Excited ferrons can form pairs with energy decreasing at higher impurity density.

Abstract

The structure of magnetic polarons (ferrons) is studied for an 1D antiferromagnetic chain doped by non-magnetic donor impurities. The conduction electrons are assumed to be bound by the impurities. Such a chain can be described as a set of ferrons at the antiferromagnetic background. We found that two types of ferrons can exist in the system. The ground state of the chain corresponds to the ferrons with the sizes of the order of the localization length of the electron near the impurity. The ferrons of the second type produce a more extended distortion of spins in the chain. They are stable within a finite domain of the system parameters and can be treated as excitations above the ground state. The ferrons in the excited states can appear in pairs only. The energy of the excited states decreases with the growth in density of impurities. This can be interpreted as a manifestation of an attractive interaction between ferrons.