Flux-periodic oscillations in the transport properties of core/shell GaAs/InAs nanowires equipped with normal and superconducting contacts

In epitaxial GaAs/InAs core/shell nanowires, the charge carriers are confined in the tubular conductor inside the InAs shell. The radial symmetry of the electronic system allows the electronic transport to be controlled using an axially aligned magnetic field via the Aharonov-Bohm effect [1]. Moreover, GaAs/InAs core/shell nanowires in combination with superconducting electrodes are a very interesting platform for flux-controlled Josephson junctions or, when covered with a superconducting full shell, for Majorana devices employing the Little-Parks effect. Recently, we have succeeded in growing crystallographically phase-pure core/shell nanowires that exhibit uniform electrical, mechanical, and optical properties [2]. We have performed magnetotransport measurements on this type of nanowires and compared their properties with those of their polymorphic counterparts. Distinct h/e-peroidic Aharonov-Bohm type oscillations in the magnetoconductance were observed in both cases, with exceptionally large oscillation amplitudes in phase-pure GaAs/InAs core/shell nanowires. Moreover, pronounced h/2e periodic oscillations of the critical current as a function of the axial magnetic field were found in Josephson junctions fabricated from polymorphic GaAs/InAs core/shell nanowires with an in-situ deposited superconducting Al half-shell.[1] F. Haas, P. Zellekens, T. Wenz, N. Demarina, T. Rieger, M. I. Lepsa, D. Grützmacher, H. Lüth, and T. Schäpers, Nanotechnology, 28, 445202 (2017).[2] M. M. Jansen, P. Perla, M. Kaladzhian, N. von den Driesch, J. Janssen, M. Luysberg, M. I. Lepsa, D. Grützmacher, and A. Pawlis, ACS Applied Nano Materials 3, 11037 (2020)