Junctions and Superconducting Symmetry in Twisted Bilayer Graphene

Junctions provide a wealth of information on the symmetry of the order parameter of superconductors. We analyze junctions between a scanning tunneling microscope (STM) tip and superconducting twisted bilayer graphene (TBG) and TBG Josephson junctions (JJs). We compare superconducting phases that are...

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Bibliographic Details
Published inPhysical review letters Vol. 131; no. 1; p. 016003
Main Authors Sainz-Cruz, Héctor, Pantaleón, Pierre A, Phong, Võ Tiến, Jimeno-Pozo, Alejandro, Guinea, Francisco
Format Journal Article
LanguageEnglish
Published United States 07.07.2023
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Summary:Junctions provide a wealth of information on the symmetry of the order parameter of superconductors. We analyze junctions between a scanning tunneling microscope (STM) tip and superconducting twisted bilayer graphene (TBG) and TBG Josephson junctions (JJs). We compare superconducting phases that are even or odd under valley exchange (s- or f-wave). The critical current in mixed (s and f) JJs strongly depends on the angle between the junction and the lattice. In STM-TBG junctions, due to Andreev reflection, the f-wave leads to a prominent peak in subgap conductance, as seen in experiments.
ISSN:1079-7114
DOI:10.1103/PhysRevLett.131.016003