Magnetoconductance oscillations in quasiballistic multimode nanowires

TL;DR

This paper investigates magnetoconductance oscillations in quasi-one-dimensional nanowires, revealing how quantum interference, spin effects, and device configuration influence conductance patterns, providing insights into the electronic structure of multichannel nanowires.

Contribution

The study introduces a detailed theoretical analysis of magnetoconductance oscillations in multichannel nanowires, highlighting the effects of quantum interference, spin-orbit coupling, and device geometry.

Findings

Magnetoconductance oscillations are aperiodic due to Zeeman splitting and field misalignment.

Higher-order tunneling processes significantly influence conductance in four-terminal setups.

The results offer a method to probe electronic structures in InAs nanowires.

Abstract

We calculate the conductance of quasi-one-dimensional nanowires with electronic states confined to a surface charge layer, in the presence of a uniform magnetic field. Two-terminal magnetoconductance (MC) between two leads deposited on the nanowire via tunnel barriers is dominated by density-of-states (DOS) singularities, when the leads are well apart. There is also a mesoscopic correction due to a higher-order coherent tunneling between the leads for small lead separation. The corresponding MC structure depends on the interference between electron propagation via different channels connecting the leads, which in the simplest case, for the magnetic field along the wire axis, can be crudely characterized by relative winding numbers of paths enclosing the magnetic flux. In general, the MC oscillations are aperiodic, due to the Zeeman splitting, field misalignment with the wire axis, and a finite extent of electron distribution across the wire cross section, and are affected by spin-orbit coupling. The quantum-interference MC traces contain a wealth of information about the electronic structure of multichannel wires, which would be complimentary to the DOS measurements. We propose a four-terminal configuration to enhance the relative contribution of the higher-order tunneling processes and apply our results to realistic InAs nanowires carrying several quantum channels in the surface charge-accumulation layer.