Switching graphitic polytypes in elastically coupled cavities

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Graphitic polytypes, stacking variants of graphene, possess unique properties like polarization and magnetism.
• Previous methods for switching polytypes were limited by large scales and high forces, hindering practical applications.

Purpose of the Study:

• To demonstrate fully reversible transformations of graphene polytypes at the 30-nanometer scale.
• To achieve this using ultra-low lateral shear forces and minimal energy per switching event.
• To establish a robust route for multi-ferroic response and elastically coupled switching.

Main Methods:

• Utilized nanometer-scale cavities in a misaligned spacer to create patterned graphene structures.
• Employed conducting-probe force microscopy and force-field calculations to analyze transformations.
• Engineered cavity geometries to control elastic coupling and switching thresholds.

Main Results:

• Achieved reversible transformations of Bernal tetralayers to rhombohedral crystals down to 30 nm.
• Demonstrated switching using <1 nN shear forces and <1 fJ energy per event.
• Observed spontaneous switching via edge-nucleated boundary solitons at superlubric interfaces.

Conclusions:

• Developed a reconfigurable slidetronic control method for graphene polytypes.
• Established a pathway for practical multi-ferroic functionality and elastically coupled switching.
• The engineered approach offers precise control over switching dynamics and thresholds.