Strong atomic reconstruction in twisted bilayers of highly flexible InSe: Machine-Learned Interatomic Potential and continuum model approaches

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Hauptverfasser: Magorrian, Samuel J., Siddiqui, Anas, Hine, Nicholas D. M.
Format: Preprint
Veröffentlicht: 2024
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author Magorrian, Samuel J.
Siddiqui, Anas
Hine, Nicholas D. M.
author_facet Magorrian, Samuel J.
Siddiqui, Anas
Hine, Nicholas D. M.
contents The relaxation of atomic positions to their optimal structural arrangement is crucial for understanding the emergence of new physical behavior in long scale superstructures in twisted bilayers of two-dimensional materials. The amount of deviation from a rigid moiré structure will depend on the elastic properties of the constituent monolayers which for the twisted bilayer - the more flexible the monolayers are, the lower the energy required to deform the layers to maximize the areas with an energetically optimal interlayer arrangement of atoms. We investigate this atomic reconstruction for twisted bilayers of highly flexible InSe. Results using two methods are demonstrated - first we train a machine-learned interatomic potential (MLIP) to enable fully atomistic relaxations of small-twist-angle large-length-scale moiré supercells while retaining density functional theory (DFT) level accuracy. We find substantial out-of-plane corrugation and in-plane domain formation for a wide range of twist angles and moiré length scales. We then adapt an existing continuum approach and show that it can reproduce some, but not all, features of the fully atomistic calculations.
format Preprint
id arxiv_https___arxiv_org_abs_2406_19462
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Strong atomic reconstruction in twisted bilayers of highly flexible InSe: Machine-Learned Interatomic Potential and continuum model approaches
Magorrian, Samuel J.
Siddiqui, Anas
Hine, Nicholas D. M.
Materials Science
Mesoscale and Nanoscale Physics
The relaxation of atomic positions to their optimal structural arrangement is crucial for understanding the emergence of new physical behavior in long scale superstructures in twisted bilayers of two-dimensional materials. The amount of deviation from a rigid moiré structure will depend on the elastic properties of the constituent monolayers which for the twisted bilayer - the more flexible the monolayers are, the lower the energy required to deform the layers to maximize the areas with an energetically optimal interlayer arrangement of atoms. We investigate this atomic reconstruction for twisted bilayers of highly flexible InSe. Results using two methods are demonstrated - first we train a machine-learned interatomic potential (MLIP) to enable fully atomistic relaxations of small-twist-angle large-length-scale moiré supercells while retaining density functional theory (DFT) level accuracy. We find substantial out-of-plane corrugation and in-plane domain formation for a wide range of twist angles and moiré length scales. We then adapt an existing continuum approach and show that it can reproduce some, but not all, features of the fully atomistic calculations.
title Strong atomic reconstruction in twisted bilayers of highly flexible InSe: Machine-Learned Interatomic Potential and continuum model approaches
topic Materials Science
Mesoscale and Nanoscale Physics
url https://arxiv.org/abs/2406.19462