Klein tunneling of optically tunable Dirac particles with elliptical dispersions

Abstract

We have investigated electron tunneling through an atomically smooth square potential barrier for both the dice lattice and graphene under a linearly polarized off-resonant and high-frequency dressing field. We have demonstrated Klein tunneling for a nonzero angle of incidence which is due to a nonalignment of optically controllable elliptical energy dispersions for the dressed states of Dirac particles and the direction of incoming kinetic particles. This finite angle of incidence has been found to depend on the light-induced anisotropy of energy dispersion, which is a function of the electron-light coupling strength, as well as the misalignment between directions of the light polarization and the electron beam incident on the potential barrier. Additionally, we have discovered much larger off-peak transmission amplitudes for dice lattices in contrast to graphene. We anticipate that the theoretical predictions could be applied to a wide range of Dirac materials and exploited for controlling both coherent tunneling and ballistic transport of electrons in the construction of novel electronic, optical, and valleytronic nanoscale switching devices.