Density of states in finite graphene superlattices
Abstract
We have derived a formula for the density of states of a Nperiod graphene superlattice (SL), which is given as an integral over the inverse of the absolute value of the group delay velocity along the SLaxis. Using that... [ view full abstract ]
We have derived a formula for the density of states of a Nperiod graphene superlattice (SL), which is given as an integral over the inverse of the absolute value of the group delay velocity along the SLaxis. Using that formula, it was shown that density of states exhibits essentially the same structure for all values of N> 5. It was found that for E<0, the effects of finite crystal size modify dramatically the density of states of the corresponding infinite SL, whereas for E>0 and N> 5, it is only slightly modified. According to our results, the inverse of the group delay velocity is proportional to the transmission coefficient, which allows us to establish a certain correlation between the properties of the density of states and those of the Landauer conductance of the Nperiod SL. Certainly, the Landauer conductance exhibits a peak structure as a function of E, with local dips located at the same energies as those of the density of states. The same behavior was observed for the group delay velocitydependence of the Landauer conductance with E=0, which is very similar to that of the density of states. When N increases, the peak positions of both the Landauer conductance and the density of states tend to be located at those values of group delay velocity where new Dirac points appear.
Authors

Carlos Duque
(Universidad de Antioquia)

Melquiades De Dios
(Universidad de la Habana)
Topic Areas
Photonic & plasmonic nanomaterials , Optical properties of nanostructures
Session
PS3 » Poster Session (13:30  Friday, 9th December, Tipi)
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