Magnetic polaron and antiferro-ferromagnetic transition in doped bilayer CrI$_3$

TL;DR

This paper uses first-principle calculations to explain the ferromagnetic transition in doped bilayer CrI$_3$, highlighting magnetic polaron formation at low electron doping levels, which advances understanding of magnetic switching in van der Waals heterostructures.

Contribution

It provides a theoretical explanation for ferromagnetic transition and magnetic polaron formation in doped bilayer CrI$_3$, a novel insight into magnetic switching mechanisms.

Findings

Prediction of magnetic polaron formation at low electron doping

Ferromagnetic transition driven by self-trapped electrons

Limited hole self-trapping within the approximation

Abstract

Gate-induced magnetic switching in bilayer CrI$_3$ has opened new ways for the design of novel low-power magnetic memories based on van der Waals heterostructures. The proposed switching mechanism seems to be fully dominated by electrostatic doping. Here we explain, by first-principle calculations, the ferromagnetic transition in doped bilayer CrI$_3$. For the case of a very small electron doping, our calculations predict the formation of magnetic polarons ("ferrons", "fluctuons") where the electron is self-locked in a ferromagnetic droplet in an antiferromagnetic insulating matrix. The self-trapping of holes is impossible, at least, within our approximation.