Superlattice MAX Phases with A-Layers Reconstructed into 0D-Clusters, 1D-Chains, and 2D-Lattices

MAX phases are layered non-van der Waals materials made by stacking hexagonal layers of transition metal (M), a group III–VI element (A), and carbon or nitrogen (X) with the conventional chemical formula Mn+1 AXn (n = 1–3). According to our recent high-throughput calculations, 761 dynamically stable MAX phases have been found, among which 466 structures are likely to be synthesized. To find completely new structural phases, we focus on the 361 MAX systems with dynamical instabilities. A series of novel superlattices are discovered for MAX phases by reconstructing the triangular lattice of A-atoms into 0D-clusters, quasi-1D-chain, or the creation of 2D Haeckelite or Kagome-like lattices. This work opens a new avenue for discovering novel MAX phases from conventional structures without any element alloying.