# Phase field crystal model for heterostructures

## TL;DR

This paper introduces an efficient phase-field crystal model for simulating atomistic configurations in 2D heterostructures, enabling exploration of material properties across large parameter spaces with realistic interface modeling.

## Contribution

The paper develops a flexible phase-field crystal model for multi-species heterostructures, validated through benchmarking and applied to graphene-boron nitride systems.

## Key findings

- Consistent elastic properties and lattice constants in simulations.
- Realistic interface and crystal shape modeling.
- Zigzag interfaces have lowest formation energy.

## Abstract

Atomically thin 2-dimensional heterostructures are a promising, novel class of materials with groundbreaking properties. The possiblity of choosing the many constituent components and their proportions allows optimizing these materials to specific requirements. The wide adaptability comes with a cost of large parameter space making it hard to experimentally test all the possibilities. Instead, efficient computational modelling is needed. However, large range of relevant time and length scales related to physics of polycrystalline materials poses a challenge for computational studies. To this end, we present an efficient and flexible phase-field crystal model to describe the atomic configurations of multiple atomic species and phases coexisting in the same physical domain. We extensively benchmark the model for two-dimensional binary systems in terms of their elastic properties and phase boundary configurations and their energetics. As a concrete example, we demonstrate modelling lateral heterostructures of graphene and hexagonal boron nitride. We consider both idealized bicrystals and large-scale systems with random phase distributions. We find consistent relative elastic moduli and lattice constants, as well as realistic continuous interfaces and faceted crystal shapes. Zigzag-oriented interfaces are observed to display the lowest formation energy.