Science Daily  October 20, 2021 An international team of researchers (USA – Princeton University, Japan) combined tunnelling and Andreev reflection spectroscopy with the scanning tunnelling microscope to observe several key experimental signatures for unconventional superconductivity in magic angle twisted bilayer graphene (MATBG). They showed that the tunnelling spectra below the transition temperature Tc are inconsistent with those of a conventional s-wave superconductor, but rather resemble those of a nodal superconductor with an anisotropic pairing mechanism. They observed a large discrepancy between the tunnelling gap which far exceeds the mean-field BCS ratio, and the gap extracted from Andreev reflection spectroscopy. The […]