Analysis of transport properties of five‐terminal beam splitter using anisotropy of the group velocity

Abstract

SUMMARYThis paper proposes a beam splitter with one emitter and two collectors each on the left and right based on anisotropy of the group velocity. An anisotropic medium is represented by a two-dimensional square lattice tight-binding model. The transport property of the beam splitter is analyzed by means of the boundary-type solution method. At the center of the band where the anisotropy of the group velocity is strong, the incident beam is split into two and propagates along the diagonal directions of the square lattice with almost no diffraction.

Manipulation of Electron Beam Propagation by Hetero-Dimensional Graphene Junctions

“…In contrast, the contour becomes a hexagon at E = ± t , indicating highly anisotropic electron energies. This in turn suggests that the electron group velocity, normal to the equal-energy contour, is highly anisotropic at E = ± t , having six preferred directions, as shown by the blue arrows in Figure c or d. At E = t , the group velocity can be calculated as v = 1 ℏ ∇ k E | E = t = true{ ± 3 a t ℏ ( 1 , 0 ) cos true( 3 2 a k y true) − 3 a t ℏ true( 1 2 , ± 3 2 true) sin ( 3 a k x ) At E = − t , the group velocity has the same expression as eq in the reverse directions, but they are filled states in the undoped graphene, which are not to be used. This anisotropic group velocity is the intrinsic property of graphene, independent of the calculation method (see Figure S2 in Supporting Information).…”