Flux-periodic supercurrent oscillations in an Aharonov–Bohm-type nanowire Josephson junction

Recent theoretical studies highlight hollow-core semiconductor-superconductor hybrid nanowires as a promising platform to engineer topological superconductivity via the Little-Parks effect and phase-winding of the superconducting order parameter. Such nanowires exhibit enhanced spatial confinement of carriers, potentially enlarging the accessible topological phase space compared to conventional core/full-shell structures. Inspired by these insights and as an essential preliminary step, we experimentally investigate GaAs/InAs core/shell nanowires with aluminum half-shells, aiming to understand how Andreev-bound states are influenced by their complex geometric confinement. With normal contacts we observed pronounced h/e flux periodic oscillations in the magnetoconductance, which can be explained via the presence of a tubular conductive channel in the InAs shell. Conversely, the switching current in Josephson junctions oscillates with approximately half that period, i.e., h/2e, indicating a full proximitization of the InAs shell from the half-shell superconducting contacts and a successful imprint of the non-trivial geometric topology onto the Andreev transport spectrum in the junction enclosing threading magnetic flux. On these structures, we systematically studied the gate-, field-, and temperature-dependent evolution of the supercurrent. Core/shell/halfshell semiconductor-superconductor nanowire Josephson junctions are promising building blocks for topological quantum devices. The authors show that their geometry shapes the superconducting transport, with the supercurrent exhibiting magnetic-field oscillations that reflect coherent interference around the shell.