Josephson Supercurrent through the Topological Surface States of Strained Bulk HgTe
Abstract
Strained bulk HgTe is a three-dimensional topological insulator, whose surface electrons have a high mobility (∼30000cm2/Vs), while its bulk is effectively free of mobile charge carriers. These properties enable a study of transport through its unconventional surface states without being hindered by a parallel bulk conductance. Here, we show transport experiments on HgTe-based Josephson junctions to investigate the appearance of the predicted Majorana states at the interface between a topological insulator and a superconductor. Interestingly, we observe a dissipationless supercurrent flow through the topological surface states of HgTe. The current-voltage characteristics are hysteretic at temperatures below 1 K, with critical supercurrents of several microamperes. Moreover, we observe a magnetic-field-induced Fraunhofer pattern of the critical supercurrent, indicating a dominant 2π-periodic Josephson effect in the unconventional surface states. Our results show that strained bulk HgTe is a promising material system to get a better understanding of the Josephson effect in topological surface states, and to search for the manifestation of zero-energy Majorana states in transport experiments.
- Publication:
-
Physical Review X
- Pub Date:
- April 2013
- DOI:
- 10.1103/PhysRevX.3.021007
- arXiv:
- arXiv:1306.0154
- Bibcode:
- 2013PhRvX...3b1007O
- Keywords:
-
- 73.23.-b;
- 72.80.Ey;
- 73.25.+i;
- 74.45.+c;
- Electronic transport in mesoscopic systems;
- III-V and II-VI semiconductors;
- Surface conductivity and carrier phenomena;
- Proximity effects;
- Andreev effect;
- SN and SNS junctions;
- Condensed Matter - Mesoscale and Nanoscale Physics
- E-Print:
- experimental paper