Nontopological states induced by the moiré superlattce in twisted nodal superconductors

We demonstrate the emergence of gapped nontopological phases driven by the moiré superlattice in twisted nodal superconductors. The effect arises from moire Umklapp scattering between differentBogoliubov-de Gennes Dirac nodes and leads to a gap opening close to specific twist angles, determined by the Fermi surface geometry. We demonstrate the robustness of nontopological phase against interactions with self-consistent calculations and show that this phase competes with the previously predicted topological gapped phases. We estimate the relevant twist angles and discuss experimental signatures focusing on twisted Bi₂Sr₂CaCu₂O_8+x.