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

Abstract

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 para-meter 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.

Klein tunneling and Fabry-Perot resonances in the α - T 3 bilayer with aligned stacking

“…The remaining curves in this figure correspond to angles below the critical angle. Comparing the critical angle of our system, it is confined between the critical angle of 0.20 rad reported for graphene and the one of α − T 3 model, which varied by about 0.67 rad (see references [47][48][49] for further details).…”

“…This decrease is due to the disappearance of the wave function of the electrons as the width of the electrical potential barrier increases. It is noticeable that the horizontal lines with T = 1 in [47][48][49] pertain to the Klein tunneling phenomenon, while the blue line in figure 5 (ii) is linked to the super tunneling effect whatever the size of L but at α = 1 and θ = 0.…”

“…This pinnacle is reached at an intermediate α value (ranging from 0 to 1, excluding α = 1). Numerous studies [34,[49][50][51][52] have delved into this phenomenon, revealing that certain physical properties exhibit a non-monotonic dependence on α. For instance, as indicated in the previously mentioned source, the Hall conduction introduces extra steps only for particular intermediate α values (between 0 and 1).…”

Optical conductivity of gapped α−T3 materials with a deformed flat band

“…The most unusual characteristics of the α-T 3 band energy structure is the presence of a flat band in their energy dispersions in addition to a regular Dirac cone, which remains stable under various external effects, such as electric and magnetic fields or impurities. 7 This unexpected, but yet relatively simple electronic energy dispersion, has stimulated a huge amount of research on the electronic, 8-13 magnetic, 14,15 optical, [16][17][18][19] transport, [20][21][22] tunneling [23][24][25][26][27][28] and collective-excitation 29,30 properties of α-T 3 and even α-T 3 -based nanoribbons [31][32][33][34] . However, there is still one key issue remains to be addressed, i.e.…”