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, f-wave leads to a prominent peak in subgap conductance, as seen in experiments.
@article{arxiv.2211.11389,
title = {Junctions and superconducting symmetry in twisted bilayer graphene},
author = {Héctor Sainz-Cruz and Pierre A. Pantaleón and Vo Tien Phong and Alejandro Jimeno-Pozo and Francisco Guinea},
journal= {arXiv preprint arXiv:2211.11389},
year = {2023}
}
Comments
5 pages, 4 figures and supplementary material. Extended discussion and minor adjustments