Thickness and Spin Dependence of Raman Modes in Magnetic Layered Fe 3 GeTe 2

Abstract

2D layered Fe3GeTe2 has attracted increasing attention due to its high magnetic ordering temperature and novel physical properties. Lattice dynamics is a fundamental property of Fe3GeTe2, and its relationships with the number of layers and interlayer spin ordering have not yet been explored in depth. Here, by first‐principles density functional theory calculations, the phonon vibrations and Raman intensities of Fe3GeTe2 are systematically studied from the bulk to monolayer structures. Furthermore, the spin‐phonon coupling effect is investigated by considering different interlayer magnetic orderings: ferromagnetic and antiferromagnetic. It is found that the frequencies of Raman modes in Fe3GeTe2 exhibit considerable dependence on the layer number and spin ordering. The results not only reveal the notable spin‐phonon interactions in Fe3GeTe2, but also demonstrate that Raman modes can be utilized for characterizing the sample thickness and interlayer spin ordering in this 2D magnet.