Computational synthesis of substrates by crystal cleavage

Abstract

The discovery of substrate materials has been dominated by trial and error, opening the opportunity for a systematic search. We generate bonding networks for materials from the Materials Project and systematically break up to three bonds in the networks for three-dimensional crystals. Successful cleavage reduces the bonding network to two periodic dimensions. We identify 4693 symmetrically unique cleavage surfaces across 2133 bulk crystals, 4626 of which have a maximum Miller index of one. We characterize the likelihood of cleavage by creating monolayers of these surfaces and calculating their thermodynamic stability using density functional theory to discover 3991 potential substrates. Following, we identify distinct trends in the work of cleavage and relate them to bonding in the three-dimensional precursor. We illustrate the potential impact of the substrate database by identifying several improved epitaxial substrates for the transparent conductor BaSnO3. The open-source databases of predicted and commercial substrates are available at MaterialsWeb.org.

Flexible Nanogenerators Based on Enhanced Flexoelectricity in Mn3O4 Membranes

“…We show that flexoelectricity in bulk Mn 3 O 4 is subdued due to a destructive interference between the bending and shearing modes; whereas in monolayer and bilayer Mn 3 O 4 , the contribution of the shearing mode diminishes, leading to flexoelectric coefficients that are two orders of magnitude larger than other 2D materials such as MoS 2 . [ 16,25,26 ] Moreover, using a model based on clasical beam theory, we find an increasing activation of the bending mode with decreasing thickness of the oxide membranes, which further increases the flexoelectric response. We demonstrate the generation of voltages up to 6.24 V (peak to peak) using these exfoliated Mn 3 O 4 ‐membrane‐based FNGs from mechanical perturbations.…”

First-principles-driven catalyst design protocol of 2D/2D heterostructures for electro- and photocatalytic nitrogen reduction reaction

“…91 Recently, the work of cleavage of a monolayer ( E cleave ) in eqn (2), which is the energy required to cleave a unit area of a bulk material, and γ were used to evaluate the thermodynamic stability of cleaved monolayer surfaces to explore potential 2D flakes as well. 92 E slab,as-cut is the energy of the as-cut slab immediately after cleaving, which is different from the optimized one, E slab . E cleave = ( E slab,as-cut − nN bulk )/ A …”

Flexible Nanogenerators based on Enhanced Flexoelectricity in Hausmannite Membranes

“…To determine which of these terminations is more likely to result from exfoliation, we calculated their surface energies (see Methods section for details). Surface energies have been shown to correlate well with the work of adhesion 30 , which is the energy per unit area required to cleave a crystal at a particular surface. This quantity is important for determining whether a non-van der Waals crystal, such as Mn3O4, can be mechanically exfoliated into few-layer structures.…”

“…The surface energies of the two (101) terminations are shown in Figure 1f for monolayer, bilayer, and bulk geometries of Mn3O4. The surface energy of two commonly used crystal substrates, (0001) ZnO and AlN, are included as references to show the feasibility for cleavage of Mn3O4 30 . The octahedral surface termination has a lower energy for all thicknesses tested here with the bilayer having the lowest energy, which is about the same as (0001) ZnO by 1 meV/Å 2 .…”