Direct imaging and electronic structure modulation of moiré superlattices at the 2D/3D interface

Area of Science:

• Materials Science
• Condensed Matter Physics
• Surface Science

Background:

• The atomic structure at 2D/3D material interfaces critically impacts electronic and optical properties.
• Moiré engineering has successfully tailored 2D/2D interfaces but remains unexplored for 2D/3D systems.

Purpose of the Study:

• To demonstrate imaging of moiré patterns at 2D/3D interfaces.
• To explore the potential of moiré engineering for tailoring 2D/3D interfaces.

Main Methods:

• Utilized epitaxially aligned Molybdenum Disulfide (MoS2) on Gold (Au{111}) as a model system.
• Employed advanced scanning transmission electron microscopy (STEM) with a geometric convolution technique.
• Performed ab initio electronic structure calculations.

Main Results:

• Successfully imaged a crystallographic 32 Å moiré pattern at the MoS2/Au{111} interface, often obscured in conventional microscopy.
• Demonstrated that charge density is modulated according to the moiré period.
• Showcased the potential for (opto-)electronic moiré engineering at 2D/3D interfaces.

Conclusions:

• Developed a general pathway to directly image periodic modulation at 2D/3D interfaces.
• Established the feasibility of utilizing moiré patterns for property engineering at 2D/3D interfaces.
• Opened new avenues for advanced materials design and characterization.