PIRSA:22020071 Scientific Series Condensed Matter

DOI10.48660/22020071

Series: Quantum Matter

Kim, P. (2022). Toward realization of novel superconductivity based on twisted van der Waals Josephson junction in Cuprates. Perimeter Institute. https://pirsa.org/22020071

Kim, Philip. Toward realization of novel superconductivity based on twisted van der Waals Josephson junction in Cuprates. Perimeter Institute, Feb. 28, 2022, https://pirsa.org/22020071 

@misc{ pirsa_PIRSA:22020071,
  doi = {10.48660/22020071},
  url = {https://pirsa.org/22020071},
  author = {Kim, Philip},
  keywords = {Condensed Matter},
  language = {en},
  title = {Toward realization of novel superconductivity based on twisted van der Waals Josephson junction in Cuprates},
  publisher = {Perimeter Institute},
  year = {2022},
  month = {feb},
  note = {PIRSA:22020071 see, \url{https://pirsa.org}}
}

Abstract

Twisted interfaces between stacked van der Waals Cuprate crystals enable tunable Josephson coupling, utilizing anisotropic superconducting order parameters. Employing a novel cryogenic assembly technique, we fabricate high-temperature Josephson junctions with an atomically sharp twisted interface between Bi_2Sr_2CaCu_2O_{8+x} crystals. The critical current density J_c sensitively depends on the twist angle. While near 0 degree twist, J_c nearly matches that of intrinsic junctions, it is suppressed almost 2-orders of magnitude but remained finite near 45 degree. J_c also exhibits non-monotonic behavior versus temperature due to competition between two supercurrent contributions from nodal and anti-nodal regions of the Fermi surface. Near 45 degree twist angle, we observe two-period Fraunhofer interference patterns and fractional Shapiro steps at half integer values, a signature of co-tunneling Cooper pairs necessary for high temperature topological superconductivity.

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