New type of antiferromagnetic polaron and bipolaron in HTc - superconductors

TL;DR

This paper proposes a new type of polaron and bipolaron in high-temperature superconductors based on a quantum antiferromagnet model, highlighting their unique charge distribution and pairing mechanism.

Contribution

It introduces a novel polaron type arising from quantum AF interactions and describes their pairing via an AF-mediated 'glue', expanding understanding of charge carriers in HTc superconductors.

Findings

Identification of a new polaron with a 'comb'-like charge distribution.

Demonstration of bipolaron formation mediated by antiferromagnetic interactions.

Analysis of the conditions favoring these polarons in HTc materials.

Abstract

The possibility of formation of a new type of polaron based on the quantum aniferromagnet (AF) model is reported. We take into account exchange interactions between localized d-d spins of the AF, as well as the p-d interaction of the AF with p-carriers. The energy minimum is found when maximum charge density occurs on every second spin. The formation of such ``comb''-like polarons results from the damping of quantum fluctuations and the appearance of Van Vleck-like staggered magnetization. Such polarons tend to form pairs coupled by an AF ``glue''.