A structure map for AB2 type 2D materials using high-throughput DFT calculations

Abstract

Using high-throughput calculations based on the density functional theory, we construct a structure map for AB₂ type monolayers of 3844 compounds which are all the combinations of 62 elements selected from the periodic table. The structure map and its web version (http://www.openmx-square.org/2d-ab2/), which are obtained by symmetry-unconstrained geometry optimizations starting from ferromagnetic 1T, 1H and planar structures as the initial states, provide comprehensive structural trends of the 3844 compounds in two dimensional (2D) structures and correctly predict the structures of most of the existing 2D compounds such as transition metal dichalcogenides and MXenes having 1T or 1H type structures. We also summarize all the families of 1T/1H type AB₂ monolayers for each combination of groups in the periodic table on the basis of our structure map and propose new types of structures such as memory structures, which may be candidate materials for data storage applications with an extremely high areal density. In addition, planar and distorted planar structures and other geometrically characteristic structures are found through the high-throughput calculations. These characteristic structures might give new viewpoints and directions to search for unknown 2D materials. Our structure map and database will promote efforts towards the synthesis of undiscovered 2D materials experimentally and investigating the properties of new structures theoretically.