Transport Simulation of Graphene Devices with a Generic Potential in the Presence of an Orthogonal Magnetic Field.

The effect of an orthogonal magnetic field is introduced into a numerical simulator, based on the solution of the Dirac equation in the reciprocal space, for the study of transport in graphene devices consisting of armchair ribbons with a generic potential. Different approaches are proposed to reach this aim. Their efficiency and range of applicability are compared, with particular focus on the requirements in terms of model setup and on the possible numerical issues that may arise.

Effects of A Magnetic Field on the Transport and Noise Properties of a Graphene Ribbon with Antidots.

We perform a numerical simulation of the effects of an orthogonal magnetic field on charge transport and shot noise in an armchair graphene ribbon with a lattice of antidots. This study relies on our envelope-function based code, in which the presence of antidots is simulated through a nonzero mass term and the magnetic field is introduced with a proper choice of gauge for the vector potential. We observe that by increasing the magnetic field, the energy gap present with no magnetic field progressively disappears, together with features related to commensurability and quantum effects.

Effect of the Channel Length on the Transport Characteristics of Transistors Based on Boron-Doped Graphene Ribbons.

Substitutional boron doping of devices based on graphene ribbons gives rise to a unipolar behavior, a mobility gap, and an increase of the I O N / I O F F ratio of the transistor. Here we study how this effect depends on the length of the doped channel. By means of self-consistent simulations based on a tight-binding description and a non-equilibrium Green’s function approach, we demonstrate a promising increase of the I O N / I O F F ratio with the length of the channel, as a consequence of the different transport regimes in the ON and OFF states.

A tight binding and [Formula: see text] study of monolayer stanene.

Stanene is a single layer of tin atoms which has been discovered as an emerging material for quantum spin Hall related applications. In this paper, we present an accurate tight-binding model for single layer stanene near the Fermi level. We parameterized the onsite and hopping energies for the nearest, second nearest, and third nearest neighbor tight-binding method, both without and with spin orbital coupling.

High-performance solution of the transport problem in a graphene armchair structure with a generic potential.

We propose an efficient numerical method to study the transport properties of armchair graphene ribbons in the presence of a generic external potential. The method is based on a continuum envelope-function description with physical boundary conditions. The envelope functions are computed in the reciprocal space, and the transmission is then obtained with a recursive scattering matrix approach.

Atomistic boron-doped graphene field-effect transistors: a route toward unipolar characteristics.

We report fully quantum simulations of realistic models of boron-doped graphene-based field-effect transistors, including atomistic details based on DFT calculations. We show that the self-consistent solution of the three-dimensional (3D) Poisson and Schrödinger equations with a representation in terms of a tight-binding Hamiltonian manages to accurately reproduce the DFT results for an isolated boron-doped graphene nanoribbon. Using a 3D Poisson/Schrödinger solver within the non-equilibrium Green's function (NEGF) formalism, self-consistent calculations of the gate-screened scattering potentials induced by the boron impurities have been performed, allowing the theoretical exploration of the tunability of transistor characteristics.