Thin films of the metastable and elusive-Fe 2 O 3 have been epitaxially stabilized on SrTiO 3 ͑111͒ substrates. The-Fe 2 O 3 films present a ͑001͒ orientation perpendicular to the substrate and three in-plane domains measuring a few nanometers and showing atomically sharp interfaces. We argue that this domain structure, rather than the epitaxial-strain, plays an essential role in stabilizing the-Fe 2 O 3 by minimizing the energy of ͑100͒ surfaces. The-Fe 2 O 3 films show a large in-plane coercivity ϳ8 kOe which combined with the magnetoelectric character claimed for this oxide may lead to novel applications in spintronics.

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2D materials have opened a new field in materials science with outstanding scientific and technological impact. A largely explored route for the preparation of 2D materials is the exfoliation of layered crystals with weak forces between their layers. However, its application to covalent crystals remains elusive. Herein, a further step is taken by introducing the exfoliation of germanium, a narrow‐bandgap semiconductor presenting a 3D diamond‐like structure with strong covalent bonds. Pure α‐germanium is exfoliated following a simple one‐step procedure assisted by wet ball‐milling, allowing gram‐scale fabrication of high‐quality layers with large lateral dimensions and nanometer thicknesses. The generated flakes are thoroughly characterized by different techniques, giving evidence that the new 2D material exhibits bandgaps that depend on both the crystallographic direction and the number of layers. Besides potential technological applications, this work is also of interest for the search of 2D materials with new properties.

Antimonene, a monolayer of β-antimony, is increasingly attracting considerable attention, more than that of other monoelemental two-dimensional materials, due to its intriguing physical and chemical properties. Under ambient conditions, antimonene exhibits a high thermodynamic stability and good structural integrity. Some theoretical calculations predicted that antimonene would have a high oxidation tendency. However, it remains poorly investigated from the experimental point of view. In this work, we study the oxidation behavior of antimonene nanosheets (ANS) prepared by ultrasonication-assisted liquid-phase exfoliation. Using a set of forefront analytical techniques, a clear effect of sonication time on the surface chemistry of prepared ANS is found. A dynamic oxidation behavior has been observed, which upon annealing at moderate temperature (210 °C) resulted in a semiconducting behavior with a bandgap of approximately 1 eV measured by ultraviolet photoelectron spectroscopy. This study yields valuable information for future applications of antimonene and paves the way towards novel modification approaches in order to tailor its properties and complement its limitations.

We report on af ast and simple method to produce highly stable isopropanol/water (4:1) suspensions of few-layer antimonene by liquid-phase exfoliation of antimony crystals in aprocess that is assisted by sonication but does not require the addition of any surfactant. This straightforwardm ethod generates dispersions of few-layer antimonene suitable for on-surface isolation. Analysis by atomic force microscopy, scanning transmission electron microscopy, and electron energy loss spectroscopyc onfirmed the formation of highquality few-layer antimonene nanosheets with large lateral dimensions.T hese nanolayers are extremely stable under ambient conditions.T heir Raman signals are strongly thickness-dependent, which was rationalized by means of density functional theory calculations.Currently,two-dimensional (2D) materials represent one of the most active research areas.[1] Apart from various wellstablished 2D materials,s uch as graphene,h -BN,a nd MoS 2 , black phosphorus (BP) has received considerable attention over the last two years.[2] This is due to the fact that whereas graphene is an on-band-gap material and transition-metal dichalcogenides have ar elatively large band gap for certain optoelectronic applications (1.5-2.5 eV), [3] the direct band gap of few-and single-layer BP is approximately 1.5 eV, [4] and this material therefore has appealing properties for electronic and ultrafast optoelectronic applications.H owever,i solated layers of BP are extremely sensitive to the surroundings,and strongly degrade upon air exposure,w hich limits their application.[2b] Thus the discovery of new 2D materials with an appropriate band gap and stability under ambient conditions is ac hallenge of utmost importance. Along this front, antimony is ag ood candidate as it is in the same group in the periodic table as phosphorus and exhibits an allotrope closely related to BP (Figure 1a). Indeed, theoretical calculations [5] have estimated the band gap for asingle layer of antimony,orantimonene (we should point out that the name antimonene is not completely correct as there are no double bonds in its structure), to be about 1.2 eV.Antimonene has recently been isolated by mechanical exfoliation, and showed good stability under ambient conditions.[6] As for other 2D materials,m icromechanical exfoliation provides high-quality flakes but is unsuitable for mass production. Liquid phase exfoliation (LPE) has been successfully applied to generate single-or few-layer (FL) samples of several 2D materials on large scale, [7] including stable suspensions of few-layer BP.[8]Herein, we demonstrate that sonication of antimony crystals in a4 :1 isopropanol/water mixture without any surfactant produces av ery stable suspension of micrometerlarge FL antimonene over weeks,e ven under ambient conditions (see the Supporting Information for details). High-quality,f ew-layer antimonene nanosheets can thus be produced by liquid-phase exfoliation. Remarkably,t he FL antimonene suspensions and the layers isolated on surfaces are very stable,...