Inverse proximity effect in semiconductor Majorana nanowires

We study the influence of the inverse proximity effect on the superconductivity nucleation in hybrid structures consisting of semiconducting nanowires placed in contact with a thin superconducting film and discuss the resulting restrictions on the operation of Majorana-based devices. A strong paramagnetic effect for electrons entering the semiconductor together with spin–orbit coupling and van Hove singularities in the electronic density of states in the wire are responsible for the suppression of superconducting correlations in the low-field domain and for the reentrant superconductivity at high magnetic fields in the topologically nontrivial regime. The growth of the critical temperature in the latter case continues up to the upper critical field destroying the pairing inside the superconducting film due to either orbital or paramagnetic mechanism. The suppression of the homogeneous superconducting state near the boundary between the topological and non-topological regimes provides the conditions favorable for the Fulde–Ferrel–Larkin–Ovchinnikov instability.

HYSTERESIS OF THE PHASE DIAGRAM IN THE FERROMAGNET-SUPERCONDUCTOR HYBRIDS

After the 100th year anniversary of the discovery of superconductivity, the field continues to develop in several directions; including ferromagnet-superconductor hybrids.1-5 Magnetic and superconducting states are perhaps the most extreme example of mutually exclusive states. However, when combined at the nanoscale, they show new exciting properties and enhanced superconductivity. Here we report the measurements and simulation of the phase diagram of a thin superconducting film with an array of magnetic nanorods (MNR) embedded in the film. Results of the experimental measurements of the phase diagram of a PbBi superconducting film with embedded arrays of Ni nanorods are reported and compared with the simulated phase diagrams.