In this study, we examine multiple encapsulated graphene Josephson junctions to determine which mechanisms may be responsible for the supercurrent observed in the quantum Hall (QH) regime. Rectangular junctions with various widths and lengths were studied to identify which parameters affect the occurrence of QH supercurrent. We also studied additional samples where the graphene region is extended beyond the contacts on one side, making that edge of the mesa significantly longer than the opposite edge. This is done in order to distinguish two potential mechanisms: a) supercurrents independently flowing along both non-contacted edges of graphene mesa, and b) opposite sides of the mesa being coupled by hybrid electron-hole modes flowing along the superconductor/graphene boundary. The supercurrent appears suppressed in extended junctions, suggesting the latter mechanism.
@article{arxiv.1801.01447,
title = {Investigation of Supercurrent in the Quantum Hall Regime in Graphene Josephson Junctions},
author = {Anne W. Draelos and Ming Tso Wei and Andrew Seredinski and Chung Ting Ke and Yash Mehta and Russell Chamberlain and Kenji Watanabe and Takashi Taniguchi and Michihisa Yamamoto and Seigo Tarucha and Ivan V. Borzenets and Francois Amet and Gleb Finkelstein},
journal= {arXiv preprint arXiv:1801.01447},
year = {2018}
}