Flux periodic magnetoconductance oscillations in GaAs/InAs core/shell nanowires

Magnetotransport experiments on epitaxial GaAs/InAs core/shell nanowires are performed in which the InAs shell forms a tube-like conductive channel around the highly resistive GaAs core. The core/shell nanowires are grown by molecular beam epitaxy. It is found that the nanowire conductance oscillates with the magnetic field oriented parallel to its axis, with a period of the magnetic flux quantum phi(0) = h/e. Related to that, it is shown that the electronic transport is mediated by closed loop quantum states encircling the wire axis rather than by electron interference of partial waves. By means of a gate voltage the conductance at zero magnetic field can be changed between an oscillation minimum and maximum. The experimental findings are supported by numerical calculations.