Coherent magnetotransport spectroscopy in an edge-blocked double quantum wire with window and resonator coupling

We propose an electronic double quantum wire system that contains a pair of edge blocking potential and a coupling element in the middle barrier between two ballistic quantum wires. A window and a resonator coupling control between the parallel wires are discussed and compared for the enhancement of the interwire transfer processes in an appropriate magnetic field. We illustrate the results of the analysis by performing computational simulations on the conductance and probability density of electron waves in the window and resonator coupled double wire system.

Figure 1

(Color online) Schematic illustration of edge-blocked double quantum wire with (a) window coupling and (b) resonator coupling between the wires. The color scale on the right shows the potential height in meV. The effective confinement length $a_w=33.7\mathrm{nm}$ in zero magnetic field.

Figure 2

(Color online) The energy spectrum of the propagating electronic states (solid red) vs the Fourier parameter $q$, and the energy spectrum of the evanescent states (dotted blue) vs $iq$, in the double wire away from the coupling element with magnetic field $B=0.5\mathrm{T}$. The active transport modes are labeled for two energies with the notation $n_{\pm i}$, where the $+i$ and $-i$ indicate, respectively, the number of the right- and left-going active modes in the subband $n$.

Figure 3

(Color online) Upper subfigure: Conductance of an edge-blocked double quantum wire without coupling element (dashed green) and with a simple window coupling between the wires (solid red). Lower subfigure: The energy spectrum of the propagating electronic states (solid red) vs the Fourier parameter $q$, and the energy spectrum of the evanescent states (dotted blue) vs $iq$, in the asymptotic regions of the system. $B=0.5\mathrm{T}$, $\alpha =2.0\times {10}^{-4}{\mathrm{nm}}^{-2}$, and $V_0=-2.0\mathrm{meV}$.

Figure 4

(Color online) The electron probability density at $E=2.82\mathrm{meV}$ for the $n_i=$ (a) $0_{+1}$ and (b) $0_{+2}$ modes, corresponding to the solid red curve in the upper subfigure of Fig. 3. $B=0.5\mathrm{T}$ and $a_w=29.3\mathrm{nm}$.

Figure 5

(Color online) The electron probability density at $E=3.51\mathrm{meV}$ for the $n_i=$ (a) $0_{+1}$ outer and (b) $1_{+1}$ inner modes, corresponding to the solid red curve in the upper subfigure of Fig. 3. $B=0.5\mathrm{T}$ and $a_w=29.3\mathrm{nm}$.

Figure 6

(Color online) Upper subfigure: Conductance of an edge-blocked double quantum wire without coupling element (dashed green) and with a resonator coupling between the wires (solid red). Lower subfigure: The energy spectrum of the propagating electronic states (solid red) vs $q$, and the energy spectrum of the evanescent states (dotted blue) vs $iq$, in the asymptotic regions of the system. $B=0.5\mathrm{T}$, $V_0=-2V_{d_0}$, ${\alpha }_{\mathrm{R}}=0.2{\alpha }_{\mathrm{W}}$, $\beta =0.05{\beta }_0$, and $V_1=8\mathrm{meV}$.

Figure 7

(Color online) The electron probability density at $E=2.48\mathrm{meV}$ for the $n_i=\left(\mathrm{a}\right)$ $0_{+1}$ and (b) $1_{+1}$ modes, corresponding to the solid red curve in the upper subfigure of Fig. 3. $B=0.5\mathrm{T}$ and $a_w=29.3\mathrm{nm}$.

Figure 8

(Color online) Upper subfigure: Conductance of an edge-blocked double wire without coupling element (dashed green) and with a resonator coupling between the wires (solid red); and transmission probabilities of inner mode (dashed blue), outer mode (dotted peach), and the mode mixing (dash-dotted watchet) of the two modes. Lower subfigure: The energy spectrum of the propagating electronic states (solid red) vs. $q$, and the energy spectrum of the evanescent states (dotted blue) vs $iq$, in the asymptotic regions of the system. $B=0.8\mathrm{T}$, other parameters are in the text.

Figure 9

(Color online) The electron probability density at $E=1.69\mathrm{meV}$ for the $n_i=\left(\mathrm{a}\right)$ $0_{+1}$ inner and (b) $0_{+2}$ outer modes, corresponding to the solid red curve in the upper subfigure of Fig. 3. $B=0.8\mathrm{T}$ such that $a_w=25.8\mathrm{nm}$.

Figure 10

(Color online) The electron probability density at $E=2.07\mathrm{meV}$ for the $n_i=\left(\mathrm{a}\right)$ $0_{+1}$ inner and (b) $0_{+2}$ outer modes, corresponding to the solid red curve in the upper subfigure of Fig. 3. $B=0.8\mathrm{T}$ such that $a_w=25.8\mathrm{nm}$.