Gate-tunable regular and chaotic electron dynamics in ballistic bilayer graphene cavities

TL;DR

This paper investigates how gate voltage influences electron dynamics in bilayer graphene cavities, revealing a transition between regular and chaotic behavior driven by anisotropic dispersion.

Contribution

We developed a trajectory-tracing algorithm that accounts for bilayer graphene's electronic properties to analyze electron dynamics in gate-defined cavities.

Findings

Gate voltage controls transition between regular and chaotic electron trajectories.

Anisotropic dispersion leads to non-standard fermion optics phenomena.

Chaotic behavior emerges despite cavity symmetry.

Abstract

The dispersion of any given material is crucial for its charge carriers' dynamics. For all-electronic, gate-defined cavities in gapped bilayer graphene, we developed a trajectory-tracing algorithm aware of the material's electronic properties and details of the confinement. We show how the anisotropic dispersion of bilayer graphene induces chaotic and regular dynamics depending on the gate voltage, despite the high symmetry of the circular cavity. Our results demonstrate the emergence of non-standard fermion optics solely due to anisotropic material characteristics.