Many-Body Description of van der Waals Torque in Two-Dimensional Materials.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Nanotechnology

Background:

• Van der Waals (vdW) torque, driven by quantum charge fluctuations, is crucial for anisotropic material assemblies.
• Continuum Casimir-Lifshitz theory is widely used but overlooks critical atomistic effects at the nanoscale.

Purpose of the Study:

• To develop an ab initio description of vdW torque.
• To investigate nanoscale effects on vdW torque in anisotropic 2D materials.
• To reveal microscopic insights into vdW torque mechanisms.

Main Methods:

• Advanced a many-body dispersion model.
• Utilized anisotropic two-dimensional materials as a prototype system.
• Performed ab initio calculations to describe fundamental torque scaling laws.

Main Results:

• Reproduced continuum theory scaling laws, including -sin(2θ) angular dependence and positive correlation with dielectric anisotropy.
• Discovered significant nanoscale effects on torque magnitude and angle relations due to shape, bending, and orientation.
• Demonstrated nonlocal distribution of atomic forces contributing to vdW torque.

Conclusions:

• The developed model provides microscopic insights into vdW torque.
• Nanoscale tailoring offers novel ways to manipulate vdW torque in anisotropic systems.
• Findings are instrumental for exploring anisotropic low-dimensional materials.