Özet:
The term Klein tunnelling refers to the counterintuitive phenomenon in which an incoming particle can perfectly transmit through a potential barrier even when the barrier height exceeds the particle’s rest energy. This phenomenon has been made ac cessible by the properties of graphene and 3D Weyl semimetals. Recently, it has been demonstrated that the quasi-2D organic conductor α-(BEDT-TTF)2I3 exhibits a zero gap state under uniaxial pressure along the stacking axis of BEDT-TTF molecules. It has been shown that the low-energy quasiparticles in this organic compound are mass less Dirac fermions, i.e. its charge carriers obey the Weyl equation. In this Master’s thesis we investigate the tunnelling effect in α-(BEDT-TTF)2I3 under the presence of hypothetical square electric potential and magnetic field. We show that although the application of electric potential does not cause asymmetric transmission profiles in 3D Weyl semimetals, the presence of tilt parameter in the energy dispersion relation ren ders the transmission profile asymmetric in the presence of a square potential barrier with constant height. Allowed transmission angle range increases with increasing po tential barrier height. Besides, we demonstrate that the perfect transmission angles which allow the barrier to be nearly transparent are shifted by application of magnetic field on the central region.
