Atomistic mechanism and interface-structure-energetics of van der Waals epitaxy demonstrated by layered alpha-MoO3 growth on mica

Faezeh A. F. Lahiji; Davide G. Sangiovanni; Biplab Paul; Justinas Palisaitis; Per O. A. Persson; Arnaud le Febvrier; Ganpati Ramanath; Per Eklund

arXiv · 2502.10594

Atomistic mechanism and interface-structure-energetics of van der Waals epitaxy demonstrated by layered alpha-MoO3 growth on mica

Faezeh A. F. Lahiji·Davide G. Sangiovanni·Biplab Paul·Justinas Palisaitis·Per O. A. Persson·Arnaud le Febvrier·Ganpati Ramanath·Per Eklund

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Abstract

Unlike conventional epitaxy, van der Waals epitaxy (vdWE) allows nearly stress-free growth of thick films with highly oriented crystals without dislocations even for large film-substrate lattice mismatches. Despite reports of vdWE in numerous materials systems, an atomistic understanding of film/substrate interface structure that explains and predicts vdWE has remained elusive. Here, we address this knowledge gap by unveiling atomistic interface mechanisms for vdWE of alpha-MoO3(0k0) on mica(001). X-ray diffraction and electron microscopy reveal alpha-MoO3(0k0) epilayers with large columnar crystals in three non-equivalent in-plane orientations. These results, together with negligible strain buildup in continuous epilayers, confirm vdWE. Ab initio computations showing interface energy minima for these orientations correlate with high cross-interface proximity between Mo atoms in alpha-MoO3 and K in mica conducive for maximal vdW attraction. These atomistic insights on interface structure and energetics provide a crucial framework for predicting vdWE for different film/substrate combinations and designing of stress-free and/or standalone epitaxial films of layered materials such as MoO3 on layered substrates such as f-mica.

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Faezeh A. F. Lahiji, Davide G. Sangiovanni, Biplab Paul, Justinas Palisaitis, Per O. A. Persson, Arnaud le Febvrier, Ganpati Ramanath, Per Eklund. 2025-02-14. Atomistic mechanism and interface-structure-energetics of van der Waals epitaxy demonstrated by layered alpha-MoO3 growth on mica. https://arxiv.org/abs/2502.10594

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