  Bernal-stacked tetralayer graphene (4LG) exhibits intriguing low-energy
properties, featuring two massive subbands and showcasing diverse features of
topologically distinct, anisotropic Fermi surfaces, including Lifshitz
transitions and trigonal warping. Here, we study the influence of the band
structure on electron dynamics within 4LG using transverse magnetic focusing.
Our analysis reveals two distinct focusing peaks corresponding to the two
subbands. Furthermore, we uncover a pronounced dependence of the focusing
spectra on crystal orientations, indicative of an anisotropic Fermi surface.
Utilizing the semiclassical model, we attribute this orientation-dependent
behavior to the trigonal warping of the band structure. This phenomenon leads
to variations in electron trajectories based on crystal orientation. Our
findings not only enhance our understanding of the dynamics of electrons in
4LG, but also offer a promising method for probing anisotropic Fermi surfaces
in other materials.
