Affiliation
Instituto de Ciencia de Materiales de Madrid (ICMM), CSIC
Title of work
Phenomenology of Majorana zero modes in full-shell hybrid nanowires
Abstract
Full-shell nanowires have been proposed as an alternative nanowire design in the search of topological superconductivity and Majorana zero modes (MZMs). They are hybrid nanostructures consisting of a semiconductor core fully covered by a thin superconductor shell and subject to a magnetic flux. They operate at smaller magnetic fields and low g-factor in comparison to their partial-shell counterparts, and the expected MZMs appear at well-controlled regions of parameter space. We find a very rich spectral phenomenology that combines the Little-Parks modulations of the parent-gap superconductor with flux, the presence of flux dispersing Caroli-de Gennes-Matricon (CdGM) analog subgap states and the emergence of MZMs across finite flux intervals. The phase diagrams for different models of the nanowires show that the MZMs typically coexist with CdGM analogs at zero energy, rendering them gapless, except for topologically protected parameter regions or islands. In consequence, the most promising candidate to obtain topologically protected MZMs is the nanowire with a tubular-shaped core.
On the other hand, radial mode mixing can act like a topological p-wave pairing between particle-hole Bogoliuvov partners, and is therefore able to create new topologically protected MZMs in regions of the phase diagram that were orginally trivial. As a result, the phase diagram is utterly transformed and exhibits protected MZMs in around half of the parameter space.
References
[1] C. Payá, S. D. Escribano, A. Vezzosi, F. Peñaranda, R. Aguado, P. San-Jose and E. Prada, arXiv:2312.11613 (2023) (Accepted in Phys. Rev. B).
[2] P. San-Jose, C. Payá, C. M. Marcus, S. Vaitiekenas and E. Prada, Phys. Rev. B 107, 155423 (2023).
[3] S. Vaitiekenas et al. Science 367, 6458 (2020)