Numerical analysis of ballistic-electron transport in magnetic fields by using a quantum point contact and a quantum wire

Abstract

We report the numerical analysis of our experimental results for electron-wave propagation from a quantum point contact to a quantum wire. Our numerical method solves the boundary problem of a lattice model, and determines wave functions at an arbitrary site. This method also includes a recursive Careen s-function method. Our study found oscillations in the conductance, and magnetic suppression of those oscillations. For a simple model, we simulate the oscillations directly related to the channel number in the quantum wire. To understand the magnetic suppression, we investigate the dependence of the electron-wave propagation on the magnetic field using a realistic model. Numerical results show that a realistic rounded corner at the point-contact and a magnetic field could suppress the oscillations. We also discuss the transition from a classical skipping orbit with clear circular segments and focusing to a quantum edge state along a potential wall.

Atomistic full-band simulations of monolayer MoS2 transistors

“…To model ballistic quantum transport (partially considering reflection within the simulation region), propagating wave functions were obtained using a recursive scattering matrix approach [21] with perfectly absorbing boundaries. Moreover, all transport calculations were performed within an atomistic tight-binding (TB) basis of maximally localized Wannier functions (MLWFs) orbitals [22], with five centered about each Mo atom, and four centered about each S atom.…”

Rashba-Zeeman-effect-induced spin filtering energy windows in a quantum wire

“…(8) is extremely unstable due to the exponentially growing and decaying contributions of the evanescent modes when the product of transfer matrices is taken. However, this unstability can be overcomed by the following iteration technique proposed by Usuki [34]:…”

“…Moreover, only the transversal spin texture has been analyzed, while the longitudinal spin texture has not been considered seriously thus far. In this paper, using the extended Usuki transfer-matrix method [34,35] combined with the Landauer-Büttiker formula, we numerically calculate the spin conductance and the spin-polarized density distributions inside the Rashba QW in the presence of a perpendicular MF for a spin-unpolarized injection. Wide energy windows with three-component spin conductance can be achieved in this system due to the Rashba Zeeman effect, which is quite different from those of the QW with only a perpendicular MF.…”

Modeling of anisotropic two-dimensional materials monolayer HfS2 and phosphorene metal-oxide semiconductor field effect transistors

“…As in Figure 1(d), TB potentials accurately reproduce original DFT band structures. We used the scattering matrix approach to propagate injected eigenmodes from semi-infinite source and drain through the device [19].…”