Topological superconductivity in twisted 2D structures

Abstract: The notion of twisting and stacking two-dimensional van der Waals materials has emerged as a paragon for realizing novel electronic states. With the goal of engineering topological superconductivity, we go beyond the archetypal example of twisted bilayer graphene and consider structures composed of proximitized quantum wires and high-Tc cuprate superconductors. On the basis of symmetry arguments, backed by microscopic modelling, these setups are predicted to spontaneously break time reversal symmetry and give rise to topological p- and d-wave phases with chiral Majorana edge modes. Given the experimental pertinence, we investigate a suite of Josephson transport phenomena in twisted cuprate bilayers and identify signatures of the topological phase. Further, the analysis is extended to twisted multilayers where the occurrence of higher order band crossings makes the groundstate susceptible to secondary instabilities and topological superconductivity appears for an extended range of twists.