Klein tunneling in graphene: optics with massless electrons
Abstract
This article provides a pedagogical review on Klein tunneling in graphene, i.e. the peculiar tunneling properties of two-dimensional massless Dirac electrons. We consider two simple situations in detail: a massless Dirac electron incident either on a potential step or on a potential barrier and use elementary quantum wave mechanics to obtain the transmission probability. We emphasize the connection to related phenomena in optics, such as the Snell-Descartes law of refraction, total internal reflection, Fabry-Pérot resonances, negative refraction index materials (the so called meta-materials), etc. We also stress that Klein tunneling is not a genuine quantum tunneling effect as it does not necessarily involve passing through a classically forbidden region via evanescent waves. A crucial role in Klein tunneling is played by the conservation of (sublattice) pseudo-spin, which is discussed in detail. A major consequence is the absence of backscattering at normal incidence, of which we give a new shorten proof. The current experimental status is also thoroughly reviewed. The Appendix contains the discussion of a one-dimensional toy model that clearly illustrates the difference in Klein tunneling between mono- and bi-layer graphene.
- Publication:
-
European Physical Journal B
- Pub Date:
- October 2011
- DOI:
- 10.1140/epjb/e2011-20351-3
- arXiv:
- arXiv:1104.5632
- Bibcode:
- 2011EPJB...83..301A
- Keywords:
-
- Critical Angle;
- Transmission Probability;
- Evanescent Wave;
- Potential Step;
- Dirac Point;
- Condensed Matter - Mesoscale and Nanoscale Physics;
- Quantum Physics
- E-Print:
- short review article, 18 pages, 14 figures