Polaronic Conductivity in Cr$_2$Ge$_2$Te$_6$ Single Crystals

TL;DR

This study investigates polaronic transport mechanisms in the 2D ferromagnetic semiconductor Cr$_2$Ge$_2$Te$_6$, revealing how magnetic anisotropy influences charge carrier hopping and offering pathways for device manipulation.

Contribution

The paper combines experimental and first-principles methods to uncover polaronic conduction in Cr$_2$Ge$_2$Te$_6$ and its dependence on magnetic anisotropy, a novel insight for 2D magnetic semiconductors.

Findings

Localized charge carriers form polarons involved in hopping conduction.

Magnetocrystalline anisotropy significantly affects polaron transport.

Potential for tuning charge transport via electron-phonon and spin-orbit interactions.

Abstract

Intrinsic, two-dimensional (2D) ferromagnetic semiconductors are an important class of materials for spin-charge conversion applications. Cr$_2$Ge$_2$Te$_6$ retains long-range magnetic order in bilayer at cryogenic temperatures and shows complex magnetic interactions with considerable magnetic anisotropy. Here, we performed a series of structural, magnetic, X-ray scattering, electronic, thermal transport and first-principles calculation studies which reveal that localized electronic charge carriers in Cr$_2$Ge$_2$Te$_6$ are dressed by surrounding lattice and are involved in polaronic transport via hopping that is sensitive on details of magnetocrystalline anisotropy. This opens possibility for manipulation of charge transport in Cr$_2$Ge$_2$Te$_6$ - based devices by electron-phonon- and spin-orbit coupling-based tailoring of polaron properties.