Diffusion Quantum Monte Carlo Benchmark of Interlayer Binding and Charge Redistribution in Chemically Distinct Two-Dimensional Van Der Waals Bilayers
Abstract
Interlayer interactions in two-dimensional materials can generate emergent phenomena absent in their constituent monolayers, including unconventional magnetic order, multiferroicity, and topological magnetic phases. Predicting such emergent behavior requires simultaneously resolving long-range dispersion, short-range orbital hybridization, and electronic correlation interactions that are intrinsically nonlocal and many-body and remain challenging even for advanced density-functional approximations. Here we establish a systematically controlled many-body benchmark for diverse bilayer materials using diffusion Monte Carlo (DMC), spanning single-sheet materials, transition-metal dichalcogenides, and magnetic transition-metal halides. We obtain equilibrium separations, binding energetics, interlayer vibrational modes, and charge redistribution, finding excellent agreement with available experiments while revealing systematic and property-dependent failures across widely used semilocal, meta-GGA, and dispersion-corrected density functionals. Beyond energetics, DMC resolves subtle interlayer charge rearrangements, particularly leading to long-ranged dipolar tails in magnetic Cr trihalides that survive well beyond the regime where semilocal DFT predicts appreciable interlayer polarization, providing a many-body basis for understanding interlayer-coupled ferroic and magnetic phenomena. The resulting energies, response properties, and high-accuracy electron densities constitute a transferable benchmark for developing next-generation density functionals. Finally, we provide a scalable high-performance-computing workflow that enables systematic expansion of many-body benchmark datasets across emerging families of layered quantum materials by the scientific community.
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BibTeX
@misc{saritas2026diffusion,
title = {{Diffusion Quantum Monte Carlo Benchmark of Interlayer Binding and Charge Redistribution in Chemically Distinct Two-Dimensional Van Der Waals Bilayers}},
author = {Kayahan Saritas and Hyeonedok Shin and Jaron T. Krogel and Anouar Benali and P. Ganesh and Paul R. C. Kent},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.05845},
eprint = {2609.05845},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.05845},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Diffusion Quantum Monte Carlo Benchmark of Interlayer Binding and Charge Redistribution in Chemically Distinct Two-Dimensional Van Der Waals Bilayers
AU - Kayahan Saritas
AU - Hyeonedok Shin
AU - Jaron T. Krogel
AU - Anouar Benali
AU - P. Ganesh
AU - Paul R. C. Kent
PY - 2026
DA - 2026/09/05
PB - arXiv
DO - 10.48550/arxiv.2609.05845
UR - https://arxiv.org/abs/2609.05845
AB - Interlayer interactions in two-dimensional materials can generate emergent phenomena absent in their constituent monolayers, including unconventional magnetic order, multiferroicity, and topological magnetic phases. Predicting such emergent behavior requires simultaneously resolving long-range dispersion, short-range orbital hybridization, and electronic correlation interactions that are intrinsically nonlocal and many-body and remain challenging even for advanced density-functional approximations. Here we establish a systematically controlled many-body benchmark for diverse bilayer materials using diffusion Monte Carlo (DMC), spanning single-sheet materials, transition-metal dichalcogenides, and magnetic transition-metal halides. We obtain equilibrium separations, binding energetics, interlayer vibrational modes, and charge redistribution, finding excellent agreement with available experiments while revealing systematic and property-dependent failures across widely used semilocal, meta-GGA, and dispersion-corrected density functionals. Beyond energetics, DMC resolves subtle interlayer charge rearrangements, particularly leading to long-ranged dipolar tails in magnetic Cr trihalides that survive well beyond the regime where semilocal DFT predicts appreciable interlayer polarization, providing a many-body basis for understanding interlayer-coupled ferroic and magnetic phenomena. The resulting energies, response properties, and high-accuracy electron densities constitute a transferable benchmark for developing next-generation density functionals. Finally, we provide a scalable high-performance-computing workflow that enables systematic expansion of many-body benchmark datasets across emerging families of layered quantum materials by the scientific community.
ER -