Abstract
Non-Hermiticity significantly enriches the concepts of symmetry and topology in physics. Particularly, non-Hermiticity gives rise to the ramified symmetries, where the non-Hermitian Hamiltonian is transformed to . For time-reversal () and sublattice symmetries, there are six ramified symmetry classes leading to novel topological classifications with various non-Hermitian skin effects. As artificial crystals are the main experimental platforms for non-Hermitian physics, there exists the symmetry barrier for realizing topological physics in the six ramified symmetry classes: while artificial crystals are in spinless classes with , nontrivial classifications dominantly appear in spinful classes with . Here, we present a general mechanism to cross the symmetry barrier. With an internal parity symmetry , the square of the combination can be modified by appropriate gauge fluxes. Using the general mechanism, we systematically construct spinless models for all non-Hermitian spinful topological phases in one and two dimensions, which are experimentally realizable. Our Letter suggests that gauge structures may significantly enrich non-Hermitian physics at the fundamental level.
- Received 2 December 2022
- Revised 15 February 2023
- Accepted 22 September 2023
DOI:https://doi.org/10.1103/PhysRevLett.131.176402
© 2023 American Physical Society