New signatures of the spin gap in quantum point contacts.

ABSTRACT: 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 ?E ? 500 ?eV. This approach could enable one-dimensional hole systems to be developed as a scalable and reproducible platform for topological quantum applications.

SUBMITTER: Hudson KL 

PROVIDER: S-EPMC7782751 | biostudies-literature | 2021 Jan

REPOSITORIES: biostudies-literature