Fe-intercalated Fe3GeTe2: Potential quasi-van der Waals magnets

Abstract

In recent years, with the fast development of magnetic devices for information technology, the demands of magnetic thin films with both high functional stability and integration flexibility rapidly increase. It is believed that building a magnet with complementary advantages of van der Waals (vdW) and non-vdW magnets, which can be described as a “quasi-vdW magnet,” will be highly appreciated. One may expect a quasi-vdW magnet to have chemical bonding between the neighboring sublayers for strong magnetic coupling, but to preserve clean surfaces with vdW feature for flexible interface engineering. For this purpose, an intercalation of magnetic atoms into the interlayer gaps of vdW magnets, as a powerful method for tuning the interlayer coupling, can be a practical approach. In this work, using the first-principles calculations, we study the potential to utilize the Fe-intercalation to transform the vdW magnets Fe3GeTe2 (FGT) into quasi-vdW magnets. As two extreme cases, it is revealed that: (i) the Fe-intercalated FGT bilayer Fe-[Fe3GeTe2]2 (Fe-[FGT]2) does have remarkable interlayer ferromagnetic coupling based on covalent bonding between the intercalated Fe atom and FGT monolayers and retains low exfoliation energy with vdW feature, suggesting that the Fe-[FGT]2 bilayer can be regarded as a quasi-vdW magnet; and (ii) the Fe-intercalation can transform the vdW FGT bulk into a non-vdW Fe-Fe3GeTe2 (Fe-FGT) bulk magnet. Accordingly, as for the intermediate cases, it is suggested that Fe-intercalated FGT multilayers (Fen−1-[FGT]n, n > 2) can also be potential quasi-vdW magnets, forming a family of magnetic thin films that provide alternative building blocks for microminiaturized magnetic devices.

Tailing the Magnetoelectric Properties of 2H-MoS2 by Engineering Covalently Bonded Mo Self-intercalation: Ferromagnetic Materials

“…The successful experimental realization of SI in 2D materials paves a new way of modulating 2D materials’ magnetoelectric properties. ,,− Compared with the progress of experiments, ,,− theoretical work is rare, ,,,,, and most works focus on 2D magnetic materials, ,− ,,,− including VS 2, CGT, CrI 3 , FeCl 2 , CrTe 2 , − and Fe 3 GeTe 2 . These self-intercalated 2D materials have CDW, working as single-atom catalysts, superconductors, , and extendable piezo/ferroelectricity …”

“…32,33,39−53 Compared with the progress of experiments, 32,33,39−52 theoretical work is rare, 29,35,37,38,54,55 and most works focus on 2D magnetic materials, 29,38−46,49,50,53−56 including VS 2, 39 CGT, 29 CrI 3 , 37 FeCl 2 , 38 CrTe 2 , 40−45 and Fe 3 GeTe 2 . 56 These self-intercalated 2D materials have CDW, 51 working as single-atom catalysts, 57 superconductors, 48,51 and extendable piezo/ferroelectricity. 58 In this article, we systematically investigate the geometry, formation energy, and magnetic and electronic properties of Mo m S n using the first-principles method.…”