Twist-angle dependent pseudo-magnetic fields in monolayer CrCl₂/graphene heterostructures

Area of Science:

• Condensed Matter Physics
• Materials Science
• 2D Materials

Background:

• Graphene exhibits unique electronic properties, including massless Dirac fermions.
• Pseudo-magnetic fields (PMFs) in graphene can mimic external magnetic fields, enabling quantum Hall effect analogues.
• Creating and controlling PMFs is crucial for exploring novel quantum phenomena.

Purpose of the Study:

• To realize a pseudo-magnetic field in epitaxial graphene.
• To investigate the properties of Landau levels generated by this pseudo-magnetic field.
• To explore the tunability of the pseudo-magnetic field strength.

Main Methods:

• Fabrication of a monolayer CrCl2/graphene heterojunction.
• Utilizing scanning tunneling spectroscopy (STS) to probe electronic states.
• Performing control experiments on CrCl2/NbSe2 interfaces.
• Varying the twist angle between CrCl2 and graphene.

Main Results:

• Successfully generated a pseudo-magnetic field in graphene via the CrCl2/graphene interface.
• Observed quantized pseudo-Landau levels associated with massless Dirac fermions using STS.
• Demonstrated that the pseudo-magnetic field strength is tunable by the twist angle, with up to threefold variation.
• Confirmed the origin of the observed phenomena as the pseudo-magnetic field in graphene.

Conclusions:

• The CrCl2/graphene heterojunction is a viable platform for generating tunable pseudo-magnetic fields.
• This system provides a novel 2D heterojunction for studying PMF-related physics, such as the valley Hall effect.
• The facile and flexible implementation of this system opens avenues for future spintronic and quantum electronic device applications.