Anisotropic properties of monolayer 2D materials: an overview from the C2DB database

TL;DR

This paper provides a comprehensive analysis of in-plane anisotropy in over a thousand 2D materials from the C2DB database, highlighting structural factors influencing anisotropy and identifying promising new compounds for future device applications.

Contribution

It offers a systematic classification and statistical analysis of anisotropic properties in 2D materials, and identifies novel, exfoliable compounds with significant anisotropic responses.

Findings

Lower symmetry correlates with higher anisotropy.

Many new compounds exhibit strong anisotropic properties.

Identified materials outperform known 2D materials in anisotropic responses.

Abstract

We analyze the occurrence of in-plane anisotropy in the electronic, magnetic, elastic and transport properties of more than one thousand 2D materials from the C2DB database. We identify hundreds of anisotropic materials and classify them according to their point group symmetry and degree of anisotropy. A statistical analysis reveals that a lower point group symmetry and a larger amount of different elements in the structure favour all types of anisotropies, which could be relevant for future materials design approaches. Besides, we identify novel compounds, predicted to be easily exfoliable from a parent bulk compound, with anisotropies that largely outscore those of already known 2D materials. Our findings provide a comprehensive reference for future studies of anisotropic response in atomically-thin crystals and point to new previously unexplored materials for the next generation of anisotropic 2D devices.