Anisotropic behaviours of massless Dirac fermions in graphene under periodic potentials
By Cheol-Hwan Park, Li Yang, Y. Son, Marvin L. Cohen, Steven G. Louie. 2008
541 citations recorded by the source corpus.
The propagation of charge carriers in graphene under an imposed periodic potential can become strongly anisotropic, suggesting a way of making electronic circuits with appropriately patterned surface electrodes without the need for cutting nanoscale structure into graphene. Graphene’s conical valence and conduction bands give rise to charge carriers that have neutrino-like linear energy dispersion and exhibit chiral behaviour near the Dirac points where these bands meet1,2,3,4,5,6. Such characteristics offer exciting opportunities for the occurrence of new phenomena and the development of high performance electronic devices. Making high quality devices from graphene, which typically involves etching it into nanoscale structures7,8,9,10, however, has proven challenging. Here we show that a periodic potential applied by suitably patterned modifications or contacts on graphene’s surface leads to further unexpected and potentially useful charge carrier behaviour. Owing to their chiral nature, the propagation of charge carriers through such a graphene superlattice is highly anisotropic, and in extreme cases results in group velocities that are reduced to zero in one direction but are unchanged in another. Moreover, we show that the density and type of carrier species (electron, hole or open orbit) in a graphene superlattice are extremely sensitive to the potential applied, and they may further be tuned by varying the Fermi level. As well as addressing fundamental questions about how the chiral massless Dirac fermions of graphene propagate in a periodic potential, our results suggest the possibility of building graphene electronic circuits from appropriately engineered periodic surface patterns, without the need for cutting or etching.
Subfields: Atomic and Molecular Physics, and Optics, Materials Chemistry, Statistical and Nonlinear Physics
View Paper: https://www.semanticscholar.org/paper/b328ff5044cdbc7e7a2a3501a835818dfc8bd8e5
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Citations in the corpus
- Colloquium: Graphene spectroscopy (2014, background): “On the other hand, Park et al. (2008b) suggested that the anisotropy of λ comes from the nonlinear band dispersion of the graphene bands at high doping.”
- Electronic and geometric corrugation of periodically rippled, self-nanostructured graphene epitaxially grown on Ru(0001) (2010, background): “Nanostructuring graphene (in stripes, dots or by periodic potentials), in turn, may reveal new physical phenomena and fascinating applications [4].”
- Surface transfer doping of semiconductors (2009, background): “Moreover, some exotic transport properties of graphene under periodic potentials can be explored by creating graphene supperlattices with alternating p–n types, which is of interest from the point of view of both fundamental physics and applications [149].”
- Electronic transport in two-dimensional graphene (2010, background): “(2007b) degeneracy or by patterning gates with a periodic super-potential (Brey and Fertig, 2009a; Park et al., 2008).”
- Emergence of superlattice Dirac points in graphene on hexagonal boron nitride (2012, background): “Numerical approaches have extended several of these results to the case of two-dimensional potentials [2, 3, 14, 15].”