Josephson effect in symmetry-mismatched van der Waals hybrid junctions of NbSe2-Bi2Sr2CaCu2O8+x and NbSe2-Bi2Sr2-xLaxCuO6+y
Abstract
Coupling superconductors of different symmetries may lead to emergent quantum phenomena but experimental studies on heterojunctions made of lattice-mismatched crystals are scarce. Here, we fabricate Josephson junction by van der Waals stacking NbSe2 flakes on freshly cleaved surfaces of Bi2Sr2CaCu2O8+x or Bi2Sr2-xLaxCuO6+y. We obtain pronounced Josephson currents across the heterojunctions at temperatures below 7 K. The Josephson coupling strength, characterized by the product of the critical Josephson current I_c and the normal state resistance R_n, can reach about 0.3 mV, much exceeding the values previously reported in Pb-Bi2Sr2CaCu2O8+x or Nb-Bi2Sr2CaCu2O8+x junctions. Microwave irradiation induces integer Shapiro steps. We also observe the Fraunhofer diffraction pattern by applying an in-plane magnetic field. We compare our results with the theoretical calculations that take into account the coherent tunneling and the order parameter mixing. Our work demonstrates the hybrid junctions as a distinctive platform for addressing pairing symmetry and emergent quantum phenomena.
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BibTeX
@misc{zhu2026josephson,
title = {{Josephson effect in symmetry-mismatched van der Waals hybrid junctions of NbSe2-Bi2Sr2CaCu2O8+x and NbSe2-Bi2Sr2-xLaxCuO6+y}},
author = {Yuying Zhu and Ziye Liu and Hongtao Yan and Lin Zhao and Xingjiang Zhou and Qi-Kun Xue and Ding Zhang},
howpublished = {arXiv},
year = {2026},
month = oct,
doi = {10.48550/arxiv.2610.29021},
eprint = {2610.29021},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2610.29021},
}
RIS
TY - UNPB
TI - Josephson effect in symmetry-mismatched van der Waals hybrid junctions of NbSe2-Bi2Sr2CaCu2O8+x and NbSe2-Bi2Sr2-xLaxCuO6+y
AU - Yuying Zhu
AU - Ziye Liu
AU - Hongtao Yan
AU - Lin Zhao
AU - Xingjiang Zhou
AU - Qi-Kun Xue
AU - Ding Zhang
PY - 2026
DA - 2026/10/21
PB - arXiv
DO - 10.48550/arxiv.2610.29021
UR - https://arxiv.org/abs/2610.29021
AB - Coupling superconductors of different symmetries may lead to emergent quantum phenomena but experimental studies on heterojunctions made of lattice-mismatched crystals are scarce. Here, we fabricate Josephson junction by van der Waals stacking NbSe2 flakes on freshly cleaved surfaces of Bi2Sr2CaCu2O8+x or Bi2Sr2-xLaxCuO6+y. We obtain pronounced Josephson currents across the heterojunctions at temperatures below 7 K. The Josephson coupling strength, characterized by the product of the critical Josephson current I_c and the normal state resistance R_n, can reach about 0.3 mV, much exceeding the values previously reported in Pb-Bi2Sr2CaCu2O8+x or Nb-Bi2Sr2CaCu2O8+x junctions. Microwave irradiation induces integer Shapiro steps. We also observe the Fraunhofer diffraction pattern by applying an in-plane magnetic field. We compare our results with the theoretical calculations that take into account the coherent tunneling and the order parameter mixing. Our work demonstrates the hybrid junctions as a distinctive platform for addressing pairing symmetry and emergent quantum phenomena.
ER -