Superconducting proximity effect in a transparent van der Waals superconductor-metal junction
Jing Li, Han-Bing Leng, Hailong Fu, Kenji Watanabe, Takashi Taniguchi, Xin Liu, Chao‐Xing Liu, Jun Zhu
Abstract
We report on Andreev reflections at clean $\mathrm{NbS}{\mathrm{e}}_{2}$-bilayer graphene junctions. The high transparency of the junction, which manifests as a large conductance enhancement of up to 1.8, enables us to see clear evidence of a proximity-induced superconducting gap in bilayer graphene and two Andreev reflections through a vertical $\mathrm{NbS}{\mathrm{e}}_{2}$-graphene and a lateral graphene-graphene junction, respectively. Quantum transport simulations capture the complexity of the experimental data and illuminate the impact of various microscopic parameters on the transmission of the junction. Our work establishes the practice and understanding of an all-van-der-Waals, high-performance superconducting junction. The realization of a highly transparent proximized graphene-graphene junction opens up possibilities to engineer emergent quantum phenomena.