The lack of large-area synthesis processes on substrates compatible with industry requirements has been one of the major hurdles facing the integration of 2D materials in mainstream technologies. This is particularly the case for the recently discovered monoelemental group V 2D materials which can only be produced by exfoliation or growth on exotic substrates. Herein, to overcome this limitation, we demonstrate a scalable method to synthesize antimonene on germanium substrates using solid-source molecular beam epitaxy. This emerging 2D material has been attracting a great deal of attention due to its high environmental stability and its outstanding optical and electronic properties. In situ low energy electron microscopy allowed the real time investigation and optimization of the 2D growth. Theoretical calculations combined with atomic-scale microscopic and spectroscopic measurements demonstrated that the grown antimonene sheets are of high crystalline quality, interact weakly with germanium, exhibit semimetallic characteristics, and remain stable under ambient conditions. This achievement paves the way for the integration of antimonene in innovative nanoscale and quantum technologies compatible with the current semiconductor manufacturing.

Magnetic skyrmions are chiral spin textures that hold great promise as nanoscale information carriers. Since their first observation at room temperature, progress has been made in their currentinduced manipulation, with fast motion reported in stray-field-coupled multilayers. However, the complex spin textures with hybrid chiralities and large power dissipation in these multilayers limit their practical implementation and the fundamental understanding of their dynamics. Here, we report on the current-driven motion of Néel skyrmions with diameters in the 100-nm range in an ultrathin Pt/Co/MgO trilayer. We find that these skyrmions can be driven at a speed of 100 m s −1 and exhibit a drive-dependent skyrmion Hall effect, which is accounted for by the effect of pinning. Our experiments are well substantiated by an analytical model of the skyrmion dynamics as well as by micromagnetic simulations including material inhomogeneities. This good agreement is enabled by the simple skyrmion spin structure in our system and a thorough characterization of its static and dynamical properties.

The reversible transformations of thin magnetite (Fe 3 O 4 ) and hematite (α-Fe 2 O 3 ) films grown on Pt(111) and Ag(111) single crystals as support have been investigated by a combined low energy electron microscopy (LEEM) and low-energy electron diffraction (LEED) study. The conversions were driven by oxidation, annealing in ultrahigh vacuum (UHV), or Fe deposition with subsequent annealing. As expected, the oxidation of a Fe 3 O 4 film yielded an α-Fe 2 O 3 structure. Unexpectedly, the annealing in UHV also led to a transformation from Fe 3 O 4 into α-Fe 2 O 3 , but only if Pt(111) was used as substrate. In contrast, on a Ag(111) substrate the inverse reaction, a slow transformation from α-Fe 2 O 3 into Fe 3 O 4 , was observed, as expected for oxygen desorption. Fe deposition on α-Fe 2 O 3 and subsequent annealing in UHV transformed the film into Fe 3 O 4 . As the most probable explanation we propose that the UHV conversion on Pt(111) supports proceeds by Fe cation diffusion through the film and Fe atom dissolution in the substrate, decreasing the Fe concentration within the iron oxide film. This process is not possible for a Ag(111) substrate. The interconversions, which were best observable in mixed films containing domains of both oxides, occurred by growth of one domain type with well-defined boundaries and growth rates.

Two-dimensional (2D) Dirac-like electron gases have attracted tremendous research interest ever since the discovery of free-standing graphene [1-3]. The linear energy dispersion and non-trivial Berry phase play the pivotal role in the remarkable electronic, optical, mechanical and chemical properties of 2D Dirac materials [4]. The known 2D Dirac materials are gapless only within certain approximations, for example, in the absence of SOC. Here we report a route to establishing robust Dirac cones in 2D materials with nonsymmorphic crystal lattice. The nonsymmorphic symmetry enforces Dirac-like band dispersions around certain high-symmetry momenta in the presence of SOC [5, 6]. Through µ-ARPES measurements we observe Dirac-like band dispersions in α-bismuthene. The nonsymmorphic lattice symmetry is confirmed by µ-LEED and STM. Our firstprinciples simulations and theoretical topological analysis demonstrate the correspondence between nonsymmorphic symmetry and Dirac states. This mechanism can be straightforwardly generalized to other nonsymmorphic materials. The results open the door for the search of symmetry enforced Dirac fermions in the vast uncharted world of nonsymmorphic 2D materials.

The recent discovery of magnetic van der Waals (vdW) materials triggered a wealth of investigations in materials science and now offers genuinely new prospects for both fundamental and applied research. Although the catalog of vdW ferromagnets is rapidly expanding, most of them have a Curie temperature below 300 K, a notable disadvantage for potential applications. Combining element-selective X-ray magnetic imaging and magnetic force microscopy, we resolve at room temperature the magnetic domains and domain walls in micron-sized flakes of the CrTe2 vdW ferromagnet. Flux-closure magnetic patterns suggesting an in-plane six-fold symmetry are observed. Upon annealing the material above its Curie point (315 K), the magnetic domains disappear. By cooling back the sample, a different magnetic domain distribution is obtained, indicating material stability and lack of magnetic memory upon thermal cycling. The domain walls presumably have Néel texture, are preferentially oriented along directions separated by 120°, and have a width of several tens of nanometers. Besides microscopic mapping of magnetic domains and domain walls, the coercivity of the material is found to be of a few millitesla only, showing that the CrTe2 compound is magnetically soft. The coercivity is found to increase as the volume of the material decreases.