Making chiral topological superconductors from nontopological superconductors through large angle twists

The material realization of the intrinsic chiral topological superconductivity (TSC) is still a big challenge in modern condensed-matter physics. In this paper, we propose a general scheme to make chiral TSCs from nontopological superconductivities (SCs) through the newly developed "twistronics"technique. Suppose we have a Dn-symmetric monolayer carrying nontopological SC with pairing angular momentum L=n/2. Here we propose that by stacking two such monolayers with the largest twist angle, the interlay Josephson coupling can drive chiral TSC with the same L in the system. An argument based on the universal Ginzburg-Landau theory is provided to understand this proposal. One known example which fits our proposal is the d+id chiral TSC in the 45°-twisted bilayer cuprates. Here, we demonstrate the application of our proposal to a new example, i.e., the f+if chiral TSC obtained by twisting two properly doped honeycomb-Hubbard-model monolayers by the angle 30°. This example is related to the newly synthesized 30°-twisted bilayer graphene.