11 June 2024 Tue 4 pm

Mesoscopic physics, emerging as a new field of physics in the late 1980ies, remains a fascinating realm with ray/particle-wave correspondence being one of its central and successful concepts. We will use and illustrate this approach in addressing Dirac fermion optics in single layer graphene billiards by trajectory tracing of relativistic electrons. A similar approach, based on generalized Fresnel laws, is applied to isotropic bilayer graphene cavities. We focus on the far-field emission characteristics that is ruled by the presence of (anti) Klein tunneling [1].

Bilayer graphene billiards offer another fascinating property in form an momentum space anisotropy known as trigonal warping of the Fermi line. Its presence alters the real space dynamics dramatically, in particular it challenges the basic assumption of particle billiards dynamics, namely that the angles of incidence and reflection are equal. Violation of this rule in bilayer graphene induces chaotic dynamics even in circular cavities. The internal and external electron dynamics can be controlled in various ways by designing the cavity’s geometric shape or adjusting externally controllable parameters such as gate voltages, Fermi energy, band gaps or the cavity orientation [2] in order to realize the desired properties of the electron dynamics.

[1] J. K. Schrepfer et al., PRB 104, 155436 (2021).

[2] L. Seemann et al., PRB 107, 205404 (2023) and arXiv:2403.10201 (2024).

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