Chiral tunneling through the single barrier structure based on the α-T3 model

The transmission coefficient T of the Dirac quasielectrons through a rectangular potential barrier in the α-T3 model is calculated and analyzed in the continuum approach. The dependence of the transmission rate on parameter α, which characterizes the degree of coupling of the central atom with the atoms in the vertices of the hexagonal lattice, and parameter β, which is equal to the ratio of Fermi velocities in the barrier and out-of-barrier regions, is analyzed. It was found, for certain quasiparticle energies, the supertunneling phenomenon is observed, which is that the transmission coefficient is equal to one independently of an angle of the particle incidence on the barrier, provided that α = 1. The values of these energies depend on the barrier height and the parameter β. It is shown that for some sets of parameters the function T(α) has maxima in the range 0< α <1. For a large range of parameter values, the transmittance increases monotonically with increasing α. For the zero angle of incidence of quasiparticles on the barrier the Klein paradox is observed, i.e., the quantum transparency of the system is ideal, and this is true for any values of parameters α, β, barrier height, and energy of quasiparticles. (author)