New signatures of the spin gap in quantum point contacts.
Springer Science and Business Media LLC
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Hudson, K., Srinivasan, A., Goulko, O., Adam, J., Wang, Q., Yeoh, L., Klochan, O., et al. (2021). New signatures of the spin gap in quantum point contacts.. Nat Commun, 12 (1) https://doi.org/10.1038/s41467-020-19895-3
One dimensional semiconductor systems with strong spin-orbit interaction are both of fundamental interest and have potential applications to topological quantum computing. Applying a magnetic field can open a spin gap, a pre-requisite for Majorana zero modes. The spin gap is predicted to manifest as a field dependent dip on the first 1D conductance plateau. However, disorder and interaction effects make identifying spin gap signatures challenging. Here we study experimentally and numerically the 1D channel in a series of low disorder p-type GaAs quantum point contacts, where spin-orbit and hole-hole interactions are strong. We demonstrate an alternative signature for probing spin gaps, which is insensitive to disorder, based on the linear and non-linear response to the orientation of the applied magnetic field, and extract a spin-orbit gap ΔE ≈ 500 μeV. This approach could enable one-dimensional hole systems to be developed as a scalable and reproducible platform for topological quantum applications.
Article, /639/766/119/1000/1016, /639/766/119/1001, /639/766/483, /120, article
External DOI: https://doi.org/10.1038/s41467-020-19895-3
This record's URL: https://www.repository.cam.ac.uk/handle/1810/315659
Attribution 4.0 International (CC BY 4.0)
Licence URL: https://creativecommons.org/licenses/by/4.0/