Adiabatic Edge Channel Transport in a Nanowire Quantum Point Contact Register

Nano Lett. 2016 Jul 13;16(7):4569-75. doi: 10.1021/acs.nanolett.6b01840. Epub 2016 Jun 30.

Abstract

We report on a prototype device geometry where a number of quantum point contacts are connected in series in a single quasi-ballistic InAs nanowire. At finite magnetic field the backscattering length is increased up to the micron-scale and the quantum point contacts are connected adiabatically. Hence, several input gates can control the outcome of a ballistic logic operation. The absence of backscattering is explained in terms of selective population of spatially separated edge channels. Evidence is provided by regular Aharonov-Bohm-type conductance oscillations in transverse magnetic fields, in agreement with magnetoconductance calculations. The observation of the Shubnikov-de Haas effect at large magnetic fields corroborates the existence of spatially separated edge channels and provides a new means for nanowire characterization.

Keywords: Adiabatic transport; InAs nanowire; Shubnikov−de Haas effect; edge channels; quantum point contacts.