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

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 1D-to-1D tunneling in experimental data.