Carbon nanotube field-effect transistors have been studied in recent years as a potential alternative to CMOS devices because of their capability of ballistic transport. In order to account properly for ballistic transport we solve the coupled Poisson and Schrödinger equations for the analysis of these devices. Conventionally the coupled Schrödinger-Poisson equation is solved iteratively with a...

Conductance quantization at room temperature is a key requirement for the utilizing of ballistic transport for, e.g., high-performance, low-power dissipating transistors operating at the upper limit of "on"-state conductance or multivalued logic gates. So far, studying conductance quantization has been restricted to high-mobility materials at ultralow temperatures and requires sophisticated nan...

We consider the dynamics of noninteracting quantum particles on a square lattice in the presence of a magnetic flux α and a dc electric field E oriented along the lattice diagonal. In general, the adiabatic dynamics will be characterized by Bloch oscillations in the electrical field direction and dispersive ballistic transport in the perpendicular direction. For rational values of α and a corre...

The transport of excitation probabilities amongst weakly coupled subunits is investigated for a class of finite quantum systems. It is demonstrated that the dynamical behavior of the transported quantity depends on the considered length scale; e.g., the introduced distinction between diffusive and ballistic transport appears to be a scale-dependent concept, especially since a transition from di...

In this paper, we present the main issues and the modelling approaches for the simulation of nanoscale MOSFETs in which transport is dominated by ballistic electrons. We show that is indeed possible to compute in an accurate way the density of states in the channel in the case of quantum confinement without solving the complete two-dimensional Schr€ odinger equation. We are developing modelling...

Techniques to engineer a MOSFET’s channel in the lateral direction have been proposed to enhance the device performance. In this paper, we present a thorough simulation study to evaluate the feasibility of such lateral engineering techniques. Each of three types of transport equations, the ballistic Boltzmann, drift-diffusion and nonequilibrium Green’s function with scattering, is solved self-c...

Ab initio density functional theory and ballistic transport theory are applied to the calculation of tunneling current through ultra-thin SiO2 gate dielectrics. The Si/SiO2/Si model interface has been constructed by orienting a crystalline SiO2 (β−cristobalite) slab such that the misfit with Si (001) was minimized and no dangling bonds appear at the interface. The structure was then sandwiched ...

We present ab initio calculations of the spin-dependent electronic transport in Fe/GaAs/Fe and Fe/ZnSe/Fe ~001! junctions simulating the situation of a spin-injection experiment. We follow a ballistic Landauer-Büttiker approach for the calculation of the spin-dependent dc conductance in the linear-response regime, in the limit of zero temperature. We show that the bulk band structure of the lea...

Semiconductor nanowires have opened new research avenues in quantum transport owing to their confined geometry and electrostatic tunability. They have offered an exceptional testbed for superconductivity, leading to the realization of hybrid systems combining the macroscopic quantum properties of superconductors with the possibility to control charges down to a single electron. These advances b...

When the dimensions of a metallic conductor are reduced so that they become comparable to the de Broglie wavelengths of the conduction electrons, the absence of scattering results in ballistic electron transport and the conductance becomes quantized. In ferromagnetic metals, the spin angular momentum of the electrons results in spin-dependent conductance quantization and various unusual magneto...