Giant Magnetoconductance Oscillations in Hybrid Superconductor−Semiconductor Core/Shell Nanowire Devices

Abstract

The magnetotransport of GaAs/InAs core/shell nanowires contacted by two superconducting Nb electrodes is investigated, where the InAs shell forms a tube-like conductive channel around the highly resistive GaAs core. By applying a magnetic field along the nanowire axis, regular magnetoconductance oscillations with an amplitude in the order of e(2)/h are observed. The oscillation amplitude is found to be larger by 2 orders of magnitude compared to the measurements of a reference sample with normal metal contacts. For the Nb-contacted core/shell nanowire the oscillation period corresponds to half a flux quantum Φ0/2 = h/2e in contrast to the period of Φ0 of the reference sample. The strongly enhanced magnetoconductance oscillations are explained by phase-coherent resonant Andreev reflections at the Nb-core/shell nanowire interface.

Aharonov-Bohm oscillations and electron gas transitions in hexagonal core-shell nanowires with an axial magnetic field

“…In particular, an axial field may lead to Aharonov-Bohm (AB) field-periodic modulation of the electron energy spectrum [11] and, if the phase-coherent length exceeds the perimeter of the NW, the observation of magnetoconductance oscillations [12,13]. Indeed, several observations of AB-like oscillations in magnetotransport experiments performed on radial heterostructures have been reported [14][15][16][17][18]. Recently, Gül et al [16] observed fluxperiodic magnetoconductance oscillations in GaAs/InAs coreshell NWs.…”

Buildup of Sn@CNT nanorods by in-situ thermal plasma and the electronic transport behaviors

“…In Fig. 6b, the differential resistance dV/dI as a function of the bias voltage is plotted at temperatures from 2 to 8 K. The distinct peaks at 2 and 3 K, are recognized as the result from Andreev reflection under a superconducting state [43,44], in which electrons/holes will be reflected from the interfaces of junction. The Andreev reflection and resultant excess conductance originates from the interfaces in Sn/CNT/Sn junctions of Sn@CNT NRs.…”

Electronic structure of quantum dots: response to the environment and externally applied fields

“…In contrast, in 3.11(b) several states with doubly-connected topology are occupied, the electron density is more delocalized and the AB-like magnetoconductance oscillations persist. The latter is indeed the usual regime in magnetotransport experiments, [96,97] what explains why only oscillating profiles have been reported in literature. …”

“…However, typical profiles show flux periodic oscillations, [96,97] and a situation with constant G has never been observed experimentally. This may be due to the fact that the most common device configuration for manipulating the electron density is to use a back-gate, instead of a gate-all-around.…”

“…[93,94] In nanowires, AB-like oscillations have also been observed in magnetotransport experiments performed on radial heterostructures. [95][96][97] Most theoretical works studying AB-related effects have considered systems with axial symmetry, but little is known about the implications of a symmetry lowering.…”