Backscattering of ballistic electrons in a corrugated-gate quantum wire

Abstract

We observe periodic oscillations in the weak magnetic-field magnetoresistance for quantum wires subjected to a corrugated gate. This enhanced magnetoresistance is attributed to backscattering of electrons from the gate corrugations due to direct ballistic trajectories through the multiple ͑open͒ quantum dot structures. Simulations of the quantum transport also show evidence of the enhanced magnetoresistance, suggesting that the classical backscattering trajectories are carried into the quantum behavior of the wire.

Magnetoresistance calculations for a quantum wire with periodically modulated width

“…The value of the Fermi energy in 'real' units is E F = 10 meV and it corresponds to the carrier density n = 3.25 × 10 15 m −2 . This value is very close to the experimental carrier density of Ochiai et al [14], n = 4 × 10 15 m −2 . All calculations are performed at zero temperature.…”

“…Even though the wire in the experimental setup of Ochiai et al [14] is quasi-ballistic, we believe it is interesting to study the influence of disorder. Diffusive systems, where the disorder is strong, have been widely investigated within the context of weak localization.…”

“…All calculations are performed at zero temperature. Therefore, we will get larger resistance fluctuations than in the experiment of Ochiai et al [14], which is performed at 0.6 K. The separation between energy levels is calculated to be 5 K at the Fermi level and 0.2 K between the two lowest lying levels in our model. It is therefore reasonable to expect that the experimental temperature of 0.6 K will have a considerable smearing effect on the resistance fluctuations.…”

“…Our model geometry is taken to reflect the experimental structure of Ochiai et al [14], and is shown in Fig. 1.…”

“…Ochiai et al have measured the magnetoresistance of ballistic quantum wires with periodically modulated width [14]. The wires were fabricated from the 2D electron gas in a GaAs/AlGaAs heterostructure.…”