Predicted High-Energy Density MN Containing Anionic 18-Crown-6 Ring-Based Polynitrogen Monolayers Acting as Cryptand.

In this study, we investigate the potential of the 18-crown-6-like two-dimensional (2D)-N structure to accommodate electrons from metals without compromising its covalent nitrogen network. Employing the crystal structure prediction enhanced by evolutionary algorithm and density functional theory methodology, we successfully predicted the existence of 16 layered M@2D-N complexes from a total of 39 MN systems investigated at 100 GPa (M = s-block Na-Cs, Be-Ba and d-block Ag, Au, Cd, Hg, Hf, W, and Y). Among those, there are 13 quenchable M@2D-N compounds that are dynamically stable at 1 atm.

Structurally Constrained Evolutionary Algorithm for the Discovery and Design of Metastable Phases.

Metastable materials are abundant in nature and technology, showcasing remarkable properties that inspire innovative materials design. However, traditional crystal structure prediction methods, which rely solely on energetic factors to determine a structure's fitness, are not suitable for predicting the vast number of potentially synthesizable phases that represent a local minimum corresponding to a state in thermodynamic equilibrium. Here, we present a new approach for the prediction of metastable phases with specific structural features and interface this method with the XtalOpt evolutionary algorithm.

Oxygen functionalized InSe and TlTe two-dimensional materials: transition from tunable bandgap semiconductors to quantum spin Hall insulators.

From first-principles calculations, we found that oxygen functionalized InSe and TlTe two-dimensional materials undergo the following changes with the increased concentrations of oxygen coverage, transforming from indirect bandgap semiconductors to direct bandgap semiconductors with tunable bandgap, and finally becoming quantum spin hall insulators. The maximal nontrivial bandgap are 0.121 and 0.

New developments in the GDIS simulation package: Integration of VASP and USPEX.

A popular first principles simulation code, the Vienna Ab initio Simulation Package (VASP), and a crystal structure prediction (CSP) package, the Universal Structure Predictor: Evolutionary Xtallography (USPEX) have been integrated into the GDIS visualization software. The aim of this integration is to provide users with a unique and simple interface through which most of the steps of a typical crystal optimization or prediction work. This involved, for the latter, not only setting up a CSP calculation with complete support for the latest version of USPEX, but also displaying the many structure results by linking each structure geometry and its energy via interactive graphics.

Prediction of a New Layered Polymorph of FeS with FeS(S) Structure.

The never-elucidated crystal structure of metastable iron disulfide FeS resulting from the full deintercalation of Li in LiFeS has been cracked thanks to crystal structure prediction searches based on an evolutionary algorithm combined with first-principles calculations accounting for experimental observations. Besides the newly layered 2/ polymorph of iron disulfide, two-dimensional dynamically stable FeS phases are proposed that contain sulfides and/or persulfide S motifs.

Copper halide diselenium: predicted two-dimensional materials with ultrahigh anisotropic carrier mobilities.

On the basis of first-principles calculations, we discuss a new class of two-dimensional materials-CuXSe (X = Cl, Br) nanocomposite monolayers and bilayers-whose bulk parent was experimentally reported in 1969. We show the monolayers are dynamically, mechanically and thermodynamically stable and have very small cleavage energies of ∼0.26 J m, suggesting their exfoliation is experimentally feasible.