Quasi-three-dimensional Green’s-function simulation of coupled electron waveguides

Abstract

A quasi-three-dimensional (3D) simulation of a quantum waveguide coupler has been performed, computing the self-consistent transverse potential along the electron waveguides and then solving the transport problem with a modified recursive Green's-function method. Results have been obtained for the tunneling conductance between the two waveguides as a function of coupling length and gate biases. A clear structure of conductance peaks is observed, strongly dependent on both the drain and the source biases. Such dependence has been investigated in greater detail for an idealized model, allowing a fast numerical simulation. A ridgelike conductance pattern has been obtained, which can be interpreted as a characteristic signature to be looked for when searching for the evidence of 113-to-1D tunneling in experimental data.

Tunneling enhancement through a barrier surrounded by a mesoscopic cavity

“…We have first computed the diagonal Green's function matrix of each slice, considered isolated from its neighbors and with Dirichlet boundary conditions at its ends [9]. Then we have used the Dyson equation to compute the Green's function matrix for adjacent coupled slices from their individual Green's functions, introducing a perturbation potentialV which connects two confining sections [10]. This procedure is repeated recursively, starting from one end of the structure and adding one slice at a time, finally obtaining the Green's function for the overall device; from this, it is easy to obtain the transmission matrix t [9].…”

Effects of short-range interactions on transport through quantum point contacts: A numerical approach

“…So the scheme reduces to the standard recursive algorithm. 32,42 If one is only interested in the current, passing the scatterer once is sufficient. After computing G 1,1 with Eq.…”

Mesoscopic effects in tunneling between parallel quantum wires

“…In reality, output characteristics depend sensitively on details of the tunneling barrier. 17 Assuming the feasibility to engineer barrier design, coupled quantum wires were suggested 18 as realizations of quantum logical gates. is applied uniformly to the upper (lower) wire, i.e., raises the chemical potential of both left-movers and right-movers.…”