We use Superconducting QUantum Interference Device (SQUID) microscopy to characterize the current-phase relation (CPR) of Josephson Junctions from 3-dimentional topological insulator HgTe (3D-HgTe). We find clear skewness in the CPRs of HgTe junctions ranging in length from 200 nm to 600 nm. The skewness indicates that the Josephson current is predominantly carried by Andreev bound states with high transmittance, and the fact that the skewness persists in junctions that are longer than the mean free path suggests that the effect may be related to the helical nature of the Andreev bound states in the surface of HgTe.
@article{arxiv.1410.1111,
title = {Non-sinusoidal current-phase relationship in Josephson junctions from the 3D topological insulator HgTe},
author = {Ilya Sochnikov and Luis Maier and Christopher A. Watson and John R. Kirtley and Charles Gould and Grigory Tkachov and Ewelina M. Hankiewicz and Christoph Brüne and Hartmut Buhmann and Laurens W. Molenkamp and Kathryn A. Moler},
journal= {arXiv preprint arXiv:1410.1111},
year = {2015}
}