Energy minimization of 2D incommensurate heterostructures

TL;DR

This paper introduces a new modeling approach for the mechanical relaxation of incommensurate 2D heterostructures that avoids supercell approximations by using local configuration space, enabling simulations of complex multilayer systems.

Contribution

The authors develop a novel parametrization method based on local configuration space, extending computational capabilities to aperiodic and multi-layer 2D heterostructures without existing interlayer potentials.

Findings

Allows true aperiodic atomistic configurations.

Enables simulation of multilayer heterostructures like MoS2.

Circumvents supercell limitations in modeling incommensurate systems.

Abstract

We derive and analyze a novel approach for modeling and computing the mechanical relaxation of incommensurate 2D heterostructures. Our approach parametrizes the relaxation pattern by the compact local configuration space rather than real space, thus bypassing the need for the standard supercell approximation and giving a true aperiodic atomistic configuration. Our model extends the computationally accessible regime of weakly coupled bilayers with similar orientations or lattice spacing, for example materials with a small relative twist where the widely studied large-scale moire patterns arise. Our model also makes possible the simulation of multi-layers for which no interlayer empirical atomistic potential exists, such as those composed of MoS2 layers, and more generally makes possible the simulation of the relaxation of multi-layer heterostructures for which a planar moire pattern does not exist.