Tuning the Fano factor of graphene via Fermi velocity modulation

Abstract

In this work we investigate the influence of a Fermi velocity modulation on the Fano factor of periodic and quasi-periodic graphene superlattices. We consider the continuum model and 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 x. 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 experimentally to identify the Dirac point. 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 symmetric when the Fermi velocity $v_A$ and $v_B$ is exchanged, however by introducing quasi-periodicity the symmetry is lost. The Fano factor usually holds a universal value for a specific transport regime, which reveals that the possibility of controlling it in graphene is a notable result.

7 pages, 8 figures. Accepted for publication in Physica E: Low-dimensional Systems and Nanostructures

References in corpus (15)

• Quantum-limited shot noise in graphene
• Fermi velocity engineering in graphene by substrate modification
• Shot Noise in Ballistic Graphene
• Quantum transport in Dirac materials: signatures of tilted and anisotropic Dirac and Weyl cones
• Shot Noise in Graphene
• Tomonaga-Luttinger Liquid Features in Ballistic Single-Walled Carbon Nanotubes: Conductance and Shot Noise
• Shot Noise with Interaction Effects in Single Walled Carbon Nanotubes
• Scattering in one-dimensional heterostructures described by the Dirac equation
• Controlling the energy gap of graphene by Fermi velocity engineering
• Controlling the conductance and noise of driven carbon-based Fabry-Perot devices
• Indirect band gap in graphene from modulation of the Fermi velocity
• Electronic structure of a graphene superlattice with a modulated Fermi velocity
• Electronic structure of a graphene superlattice with massive Dirac fermions
• Double-periodic quasi-periodic graphene superlattice: non-Bragg band gap and electronic transport
• Transport in graphene nanostructures with spatially modulated gap and potential

Cited by in corpus (5)

• Perfect valley filter controlled by Fermi velocity modulation in graphene
• Dirac wave transmission in Lévy disordered systems
• Effects of Fermi velocity engineering in magnetic graphene superlattices
• Electronic transport in disordered graphene superlattices with scale-free correlated barrier spacements
• Wave transmission and its universal fluctuations in one-dimensional systems with Lévy-like disorder: Schrödinger, Klein-Gordon and Dirac equations