Enhanced Interlayer Coupling and Excitons in Twin-Stacked Two-Dimensional Magnetic CrSBr Bilayers.

Area of Science:

• Condensed matter physics
• Materials science
• Quantum chemistry

Background:

• Van der Waals heterostructures enable engineering of material properties.
• Electronic coupling between layers dictates functionalities.
• CrSBr is an anisotropic 2D magnetic semiconductor with tunable properties.

Purpose of the Study:

• Investigate the relationship between twist angle and electronic coupling in CrSBr bilayers.
• Understand how interlayer coupling affects magnetic and optical properties.
• Explore the potential of twin stacking for property engineering.

Main Methods:

• State-of-the-art first-principles calculations.
• Analysis of electronic coupling as a function of twist angle.
• Correlation of coupling strength with orbital overlap and spin alignment.

Main Results:

• Electronic coupling in CrSBr bilayers is nonlinear and nonmonotonic with twist angle.
• A pronounced coupling maximum occurs at the twin-stacking configuration.
• Coupling strength depends on Br orbital overlap and interlayer spin angle.
• Enhanced coupling leads to delocalized excitons with polarization dependent on spin alignment.

Conclusions:

• Twin stacking significantly enhances interlayer electronic coupling in CrSBr bilayers.
• A sensitive interplay exists between twist angle, magnetism, and excitonic properties.
• Twin stacking presents an effective strategy for engineering interlayer coupling and functionalities in 2D heterostructures.