Joining and Arrangement of Multilayers (JAM): A string representation for honeycomb layered materials.

Herein we introduce a new and straightforward notation for identifying stacking sequences in high-symmetric honeycomb lattice layered materials. The Joining and Arrangement of Multilayers (JAM) notation assigns a string of characters to the structure of a polytype using only its chemical symbols. A pair of basic rules based on the symmetry is enough to identify those JAM strings that provide unique polytypes (canonical JAMs). This notation is the first step in transcribing layered materials into a series of characters for more accurate identification of stacking sequences.