Destructive Little-Parks Effect in a Full-Shell Nanowire-based Transmon

Andreev Modes from Phase Winding in a Full-shell Nanowire-based Transmon

We investigate transmon qubits made from semiconductor nanowires with a fully surrounding superconducting shell. In the regime of reentrant superconductivity associated with the destructive Little-Parks effect, numerous coherent transitions are observed in the first reentrant lobe, where the shell carries 2π winding of superconducting phase, and are absent in the zeroth lobe. As junction density was increased by gate voltage, qubit coherence was suppressed then lost in the first lobe. These observations and numerical simulations highlight the role of winding-induced Andreev states in the junct…

Asymmetric Little-Parks Oscillations in Full Shell Double Nanowires

Little-Parks oscillations of a hollow superconducting cylinder are of interest for flux-driven topological superconductivity in single Rashba nanowires. The oscillations are typically symmetric in the orientation of the applied magnetic flux. Using double InAs nanowires coated by an epitaxial superconducting Al shell which, despite the non-centro-symmetric geometry, behaves effectively as one hollow cylinder, we demonstrate that a small misalignment of the applied parallel field with respect to the axis of the nanowires can produce field-asymmetric Little-Parks oscillations. These are revealed…

Manipulating superconducting fluctuations by the Little-Parks-de Gennes effect in ultrasmall Al loops

The destruction of superconducting phase coherence by quantum fluctuations and the control of these fluctuations have been a problem of long-standing interest, with recent impetus provided by its relevance to the pursuit of very high temperature superconductivity. Building on the work of Little and Parks, de Gennes predicted more than three decades ago that superconductivity could be destroyed near half-integer-flux quanta in ultrasmall loops with a side branch, resulting in a destructive regime. We report the experimental observation of this Little-Parks-de Gennes effect in Al loops prepared …

Flux-induced Majorana modes in full-shell nanowires

We demonstrate a novel means of creating Majorana zero modes using magnetic flux applied to a full superconducting shell surrounding a semiconducting nanowire core, unifying approaches based on proximitized nanowires and vortices in topological superconductors. In the destructive Little-Parks regime, reentrant regions of superconductivity are associated with integer number of phase windings in the shell. Tunneling into the core reveals a hard induced gap near zero applied flux, corresponding to zero phase winding, and a gapped region with a discrete zero-energy state for flux around Φ_0 = h/2e…

通过 1$e$ 周期全壳库仑岛的超电流输运

Supercurrent transport through 1$e$-periodic full-shell Coulomb islands

本研究实验测量全超导壳半导体纳米线库仑岛的超电流，发现第零瓣为 2$e$ 周期、第一瓣平均为 1$e$ 周期并有奇偶调制，支持零能态承载超电流的理论模型。

Flux-induced topological superconductivity in full-shell nanowires

We present a novel route to realizing topological superconductivity using magnetic flux applied to a full superconducting shell surrounding a semiconducting nanowire core. In the destructive Little-Parks regime, reentrant regions of superconductivity are associated with integer number of phase windings in the shell. Tunneling into the core reveals a hard induced gap near zero applied flux, corresponding to zero phase winding, and a gapped region with a discrete zero-energy state around one applied flux quantum, Φ_0 = h/2e, corresponding to 2π phase winding. Theoretical analysis indicates that …