Expanding two-dimensional databases by combining exhaustive search and machine learning

We report an exhaustive search of 2d structures for binary and ternary compositions. The methodology consists of a combinatorial exploration of all possible Wyckoff positions of

layered groups while restricting our search to neutral compounds which follow the electronegativity Pauling test. Most elements of the periodic table were considered except

radioactive elements and rare gases. A selected set of oxidation states were used based on experimental feedback, allowing our materials to be proner to synthesis. A screening procedure is developed where pre-optimized structures are obtained by using a crafted universal potential, which is trained by using structures, energies, and forces fully optimized from DFT. We report an unprecedented amount of unreported two-dimensional structures containing the vast majority of elements in the periodic table. Using the obtained structures, we are to decorate nearly all Platonic and Archimedean tesselations and their dual Laves or Catalan tilings. We also report a vibrant space of polymorphism over materials with similar chemical compositions. We further accelerate the exploration of the available chemical space by training a machine learning prototype search by using the structures and energies found in the exhaustive search. We can then report more than 6500 compounds with energies below 250 meV/atom of the convex hull, only over binaries and ternaries.