Geometrically driven effects in curved superconducting nanostructures

Paola Gentile

The most recent advances in nanotechnology have demonstrated the possibility to create flexible semiconductor nanomaterials which are bent into curved, deformable objects ranging from semiconductor nanotubes, to nanohelices, etc. The consequences of the nanowire bending on the electronic quantum properties have been demonstrated to become of particular importance in systems with structure inversion asymmetry, where the interplay between nanoscale deformations and Rashba spin-orbit coupling (RSOC) [1] allows an all-geometrical and electrical control of electronic spin textures and spin transport properties [2,3], including the possibility to induce topological nontrivial phases [4-6]. In the presence of superconducting pairing, inversion symmetry breaking (ISB) makes neither spin nor parity good quantum numbers anymore. The ensuing mixing of even spin-singlet and odd spin- triplet channels leads to a series of novel features, from unconventional surface states to topological phases. Within this framework, we have explored the impact that nanoscale geometry has on superconducting properties of low-dimensional materials, showing that the interplay between RSOC and shape deformations can lead to novel paths for a geometric manipulation of the superconducting state, both for spin-singlet and spin-triplet quantum configurations [7], then significantly affecting the Josephson effect of weak links between Rashba coupled straight superconducting nanowires with geometric misalignment [8] as well as between nanowires of topological superconductors with non-trivial geometric curvature [9].

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