Multiscale modeling of materials based on force and charge density fidelity

Area of Science:

• Materials Science
• Computational Chemistry
• Condensed Matter Physics

Background:

• Accurate modeling of quantum solids is essential for understanding material properties.
• Existing methods often struggle to balance computational cost with accuracy for large systems.
• Multiscale modeling offers a promising approach to bridge quantum and classical descriptions.

Purpose of the Study:

• To develop and validate a multiscale modeling framework for insulating materials.
• To represent a quantum solid using an equivalent composite semiclassical solid.
• To accurately capture the electronic structure and mechanical response of materials at different scales.

Main Methods:

• Constructing classical potentials for the bulk domain based on quantum solid properties.
• Utilizing detailed quantum calculations for a local quantum domain.
• Developing 'pseudoatoms' to handle broken bonds and incorporating polarization effects.
• Quantitatively testing the model using a SiO(2) nanorod as a case study.

Main Results:

• The proposed multiscale model accurately reproduces the equilibrium structure and elastic response of a SiO(2) nanorod.
• Charge density and forces within the quantum subdomain are accurately predicted, even beyond the linear elastic regime.
• The model's accuracy is validated across different quantum chemical methods, including transfer Hamiltonian and density functional theory.

Conclusions:

• The composite semiclassical solid model provides a faithful and accurate multiscale representation of quantum solids.
• The developed method effectively incorporates environmental effects, crucial for accurate simulations of localized quantum phenomena.
• This approach offers a computationally efficient yet accurate tool for studying the behavior of insulating materials.