Diffusion Quantum Monte Carlo Benchmark of Interlayer Binding and Charge Redistribution in Chemically Distinct Two-Dimensional Van Der Waals Bilayers
Year: 2026
Type: preprint
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.
Source: arXiv (Cornell University)
Language: English
Subfield: Atomic and Molecular Physics, and Optics
Field: Physics and Astronomy
Domain: Physical Sciences
Open Access status: green
Awards: G1019100964, G102163711, G1026679911, G107546177, G121915436, G1286251239, G1313983767, G1645119126, G1664757510, G166562317, G203625172, G2287611682, G262962599, G2757267231, G2988778103, G2998698001, G3075337988, G313676650, G426311843, G498139845, G5387317844, G5726405315, G6144542739, G6848031779, G6918803902, G7583137537, G807938293, G8269158468, G8906985441, G8943143067, G969889393, G993149817
OpenAlex ID: W7212017445