Computational discovery and characterization of polymorphic two-dimensional IV –V materials

First-principles calculations predict the stability andproperties of two-dimensional (2D) group IV –V MX compounds (M = Si,Ge, Sn, Pb; X  = P, As, Sb, Bi) in two distinct crystallographic configurations: a low symmetryCm layer inspired by the layered bulkstructures of SiP, SiAs, GeP, and GeAs, and a high symmetryP6¯m2structure previously predicted for 2D SiP. The calculations predict that theCmstructure is more stable for X  = As, Sb, and Bi, and theP6¯m2structure for X  = P. The electronicproperties of the twostructures are quite different. Specifically, theCmband gaps are systematically larger by about 15% for most compounds, and the band offsets indicate that all of these compounds in theCmcrystal structure will form type IIheterojunctions in contact with theirP6¯m2 polymorphs. Pourbaix diagrams predict that a few of the 2D IV –V compounds are stable when exposed to water.

Source: Applied Physics Letters - November 8, 2016 Category: Physics Authors: Michael Ashton, Susan B. Sinnott and Richard G. Hennig Source Type: research