We investigate electron transport through the interface between a niobium superconductor and the edge of a two-dimensional semimetal, realized in a 20~nm wide HgTe quantum well. Experimentally, we observe that typical behavior of a single Andreev contact is complicated by both a pronounced zero-bias resistance anomaly and shallow subgap resistance oscillations with 1/n periodicity. These results are demonstrated to be independent of the superconducting material and should be regarded as specific to a 2D semimetal in a proximity with a superconductor. We interpret these effects to originate from the Andreev-like correlated process at the edge of a two-dimensional semimetal.
@article{arxiv.1511.08085,
title = {Andreev reflection at the edge of a two-dimentional semimetal},
author = {A. Kononov and S. V. Egorov and Z. D. Kvon and N. N. Mikhailov and S. A. Dvoretsky and E. V. Deviatov},
journal= {arXiv preprint arXiv:1511.08085},
year = {2016}
}