Above-room-temperature chiral skyrmion lattice and Dzyaloshinskii–Moriya interaction in a van der Waals ferromagnet Fe3−xGaTe2

Skyrmions in existing 2D van der Waals (vdW) materials have primarily been limited to cryogenic temperatures, and the underlying physical mechanism of the Dzyaloshinskii–Moriya interaction (DMI), a crucial ingredient for stabilizing chiral skyrmions, remains inadequately explored. Here, we report the observation of Néel-type skyrmions in a vdW ferromagnet Fe3−xGaTe2 above room temperature. Contrary to previous assumptions of centrosymmetry in Fe3−xGaTe2, the atomic-resolution scanning transmission electron microscopy reveals that the off-centered FeΙΙ atoms break the spatial inversion symmetry, rendering it a polar metal. First-principles calculations further elucidate that the DMI primarily stems from the Te sublayers through the Fert–Lévy mechanism. Remarkably, the chiral skyrmion lattice in Fe3−xGaTe2 can persist up to 330 K at zero magnetic field, demonstrating superior thermal stability compared to other known skyrmion vdW magnets. This work provides valuable insights into skyrmionics and presents promising prospects for 2D material-based skyrmion devices operating beyond room temperature. There are now several van der Waals magnets that have been shown to host skyrmions, however, these are typically hampered by a low Curie temperature, restricting the temperature at which the skyrmions can exist. Here, Zhang, Jiang, Jiang and coauthors find a skyrmion lattice in the van der Waals magnet Fe3 − xGaTe2 above room temperature and demonstrate the critical role of symmetry breaking in crystal lattice in the origin of these skyrmions.