Magic-angle twisted bilayer graphene under orthogonal and in-plane magnetic fields

Area of Science:

• Condensed Matter Physics
• Materials Science
• Quantum Mechanics

Background:

• Twisted bilayer graphene exhibits unique electronic properties due to its tunable band structure.
• Understanding the influence of external fields is crucial for novel electronic device applications.

Purpose of the Study:

• To investigate the impact of magnetic fields on the band structure of magic-angle twisted bilayer graphene.
• To analyze the behavior of Landau levels and the energy gap under varying magnetic field configurations.

Main Methods:

• Utilized a tight-binding model coupled with the Peierls phase approximation.
• Calculated the energy bands for periodic two-dimensional systems in the presence of magnetic fields.

Main Results:

• Observed dispersive Landau levels for orthogonal magnetic fields, especially when magnetic lengths approach the twisted bilayer cell size.
• Demonstrated that high in-plane magnetic fields significantly modify low-energy bands and the energy gap.

Conclusions:

• The minimal coupling mechanism is directly responsible for the observed modifications in the band structure and energy gap.
• Magnetic field effects offer a pathway to tune the electronic properties of twisted bilayer graphene.