First-principles prediction of lattice coherency in van der Waals heterostructures

TL;DR

This paper develops a first-principles approach combined with an extended Frenkel-Kontorova model to predict lattice coherency in van der Waals heterostructures, successfully matching experimental data and predicting new interface types.

Contribution

It introduces a novel first-principles method linked with an extended FK model to determine lattice coherency in 2D heterostructures, including predictions of new superlattices.

Findings

Computational predictions align with experimental observations.

Predicted new superlattices and perfectly-matching interfaces.

Extended FK model effectively links first-principles calculations to interface predictions.

Abstract

The emergence of superconductivity in slightly-misaligned graphene bilayer [1] and moir\'e excitons in MoSe$_2$-WSe$_2$ van der Waals (vdW) heterostructures [2] is intimately related to the formation of a 2D superlattice in those systems. At variance, perfect primitive lattice matching of the constituent layers has also been reported in some vdW-heterostructures [3-5], highlighting the richness of interfaces in the 2D world. In this work, the determination of the nature of such interface, from first principles, is demonstrated. To do so, an extension of the Frenkel-Kontorova (FK) model [6] is presented, linked to first-principles calculations, and used to predict lattice coherency for a set of 56 vdW-heterostructures. Computational predictions agree with experiments, when available. New superlattices as well as perfectly-matching interfaces are predicted.