Electrons in a Dirac semimetals possess linear dispersion in all three spatial dimensions, and form part of a developing platform of novel quantum materials. Bi1−xSbx supports a three-dimensional Dirac cone at the Sb-induced band inversion point. Nanoscale phase-sensitive junction technology is used to induce superconductivity in this Dirac semimetal. Radio frequency irradiation experiments reveal a significant contribution of 4π-periodic Andreev bound states to the supercurrent in Nb-Bi0.97Sb0.03-Nb Josephson junctions. The conditions for a substantial 4π contribution to the supercurrent are favourable because of the Dirac cone's topological protection against backscattering, providing very broad transmission resonances. The large g-factor of the Zeeman effect from a magnetic field applied in the plane of the junction, allows tuning of the Josephson junctions from 0 to π regimes.
@article{arxiv.1707.03154,
title = {$4\pi$ periodic Andreev bound states in a Dirac semimetal},
author = {Chuan Li and Jorrit C. de Boer and Bob de Ronde and Shyama V. Ramankutty and Erik van Heumen and Yingkai Huang and Anne de Visser and Alexander A. Golubov and Mark S. Golden and Alexander Brinkman},
journal= {arXiv preprint arXiv:1707.03154},
year = {2018}
}