Elusive Dzyaloshinskii-Moriya interaction in monolayer Fe3GeTe2

Abstract

Using symmetry analysis and density functional theory calculations, we uncover the nature of Dzyaloshinskii-Moriya interaction in Fe3GeTe2 monolayer. We show that while such an interaction might result in small distortion of the magnetic texture on the short range, on the longrange Dzyaloshinskii-Moriya interaction favors in-plane Néel spin-spirals along equivalent directions of the crystal structure. Whereas our results show that the observed Néel skyrmions cannot be explained by the Dzyaloshinskii-Moriya interaction at the monolayer level, they suggest that canted magnetic texture shall arise at the boundary of Fe3GeTe2 nanoflakes or nanoribbons and, most interestingly, that homochiral planar magnetic textures could be stabilized.

Néel-type skyrmions and their current-induced motion in van der Waals ferromagnet-based heterostructures

“…S9b [30]. We would also like to note that this result of nonexisting interfacial DMI in FGT bulk crystal has also been reported recently by Laref et al [60], opposing another work by Wang et al [24] that estimates some finite DMI within FGT.…”

Tunable Néel–Bloch Magnetic Twists in Fe3GeTe2 with van der Waals Structure

“…[3][4][5][6][7][8][9][10] As theoretically predicted, typical Bloch-type bubbles appear in centrosymmetric ferromagnets (FM) with magnetic dipolar interaction while Néel-type skyrmions are favored in thin heterostructure heavy metal/ FM with interfacial DMI. [8,9,[11][12][13] Several experimental observations support such theoretical predictions: Bloch-type bubbles, stabilized by the magnetic dipolar interaction in centrosymmetric FM, were claimed in the (001) thin plates (thinned from a bulk magnet) of vdW magnets Cr 2 Ge 2 Te 6 [4] and FGT, [5,8] while Néel-type skyrmions were reported in a heterostructure WTe 2 /FGT with an estimated large interfacial DMI strength of 1.0 mJ m −2 at the interface, much larger than their calculated critical DMI value of ≈0.1 mJ m −2 necessary for stabilizing Néel-type twists including skyrmions and domain walls. [6] The stability of Néeltype skyrmions is also predicted in multilayered films, such as the Pt/oxidized-FGT/FGT [9] and FGT/[Co/Pd] n .…”

Magnetic field-induced non-trivial electronic topology in Fe3GeTe2

“…1a) in the magnetic properties of Fe 3 GeTe 2 , a biquadratic nearest-neighbours exchange of K ij = 1meV has been used. We also included an in-plane DMI value of 10% of the Heisenberg exchange implemented following the symmetry presented in Laref et al 23 . In the absence of an applied field, the ground-state is a stripe domain phase (Fig.…”

“…The observation of skyrmions [12][13][14] and spin spirals on its surface 22 can only be reconciled with a sizeable Dzyaloshinskii-Moriya interaction, whose origin is discussed in Ref. 23 , although inelastic neutron scattering would suggest negligible inter-layer exchange interactions but a prominent role for the single ion anisotropy 24 .…”