Magnetoresistance of one-dimensional subbands in tunnel-coupled double quantum wires

Abstract

We study the low-temperature in-plane magnetoresistance of tunnel-coupled quasi-onedimensional quantum wires. The wires are defined by two pairs of mutually aligned split gates on opposite sides of a I 1 micron thick AlGaAsIGaAs double quantum well heterostructure, allowing independent control of their widths. In the ballistic regime, when both wires are defined and the field is perpendicular to the current, a large resistance peak at -6 Tesla is observed with a strong gate voltage dependence. The data is consistent with a counting model whereby the number of subbands crossing the Fermi level chan, Des with fie!d due to the formation of an anticrossing in each pair of ID subbands.

Multisublevel magnetoquantum conductance in single and coupled double quantum wires

“…This behavior of the diffusive conductance obtained for asymmetric wells as well as for the low-density or large-gap samples is consistent with that observed recently for long double quantum wires. 4 On the other hand, the V-shaped quantized conductance with a minimum as shown in Figs. 5-8 is similar to that observed 4,6 recently for short double quantum wires, suggesting that the transport may be ballistic for the samples.…”

“…The channel constriction in the x direction is achieved in both channels independently through top and bottom split gates, which allow probing both the 2D-2D, 2D-1D, and 1D-1D regimes by adjusting the gate biases. 4 Electron tunneling deforms the electronic structure in the channel direction dramatically in the presence of a magnetic field B in the x direction due to the anticrossing effect as illustrated in Fig. 1͑d͒.…”

“…A recent calculation predicted, 5 for this coupled double-wire structure, that the ballistic conductance shows a V-shaped quantum staircase and decreases in steps of 2e 2 /h as a function of the field, reaches a minimum and then increases and saturates at high fields in agreement with the observed data. 4 When the ballistic conductance does not show clear quantized behavior due to thermal or level broadening, it is not possible to determine if the electronic motion is ballistic or diffusive at zero magnetic field. Therefore it is interesting to calculate the field dependence of the conductance in the two limits.…”

Spin–orbit interaction and magnetic field effects on the energy dispersion of double quantum wire

“…[12]. Several theoretical [12][13][14] and experimental [15,16] which is created with the separation of two identical narrow quantum wires by a potential barrier. In particular, Lyo and his colleagues have investigated mobility, conductivity and magnetoresistance of the coupled double quantum wires subjected to magnetic field [17,18].…”

Magnetic anticrossing of 1D subbands in ballistic double quantum wires

“…In this work, portions of which have appeared previously [4], we study a pair of vertically coupled quantum point contacts (VCQPCs) in a closely coupled GaAs/Al 0.3 Ga 0. 1.…”