Our latest work “Tuning the Fano factor of graphene via Fermi velocity modulation” has just been accepted for publication in Physica E: Low-dimensional systems and nanostructures.
In this work we investigate the influence of a Fermi velocity modulation on the Fano factor of periodic and quasi-periodic graphene superlattices. We use the transfer matrix method to solve the Dirac-like equation for graphene where the electrostatic potential, energy gap and Fermi velocity are piecewise constant functions of the position. We found that in the presence of an energy gap, it is possible to tune the energy of the Fano factor peak and consequently the location of the Dirac point, by a modulations in the Fermi velocity. Hence, the peak of the Fano factor can be used to identify the Dirac point in experiments. We show that for higher values of the Fermi velocity the Fano factor goes below 1/3 in the Dirac point. Furthermore, we show that in periodic superlattices the location of Fano factor peaks is symmetry when the Fermi velocity of the regions is swapped, however by introducing quasi-periodicity this symmetry is lost. The Fano factor usually holds a universal value for a specific transport regime, therefore the possibility of controlling it in graphene is a notable result.
The manuscript is a product of our ongoing collaboration with Prof. Jonas R. F. Lima and Prof. Anderson L. R. Barbosa at Universidade Federal Rural de Pernambuco and my departmental colleague Prof. Claudionor G. Bezerra.
The accepted paper is available here. Free access link until December 28, 2017. A free preprint version is available here.