Whereas point-gap topological phases are responsible for exceptional phenomena intrinsic to non-Hermitian systems, their realization in quantum materials is still elusive. Here, we propose a simple and universal platform of point-gap topological phases constructed from Hermitian topological insulators and superconductors. We show that ($d-1$)-dimensional point-gap topological phases are realized by making a boundary in $d$-dimensional topological insulators and superconductors dissipative. A crucial observation of the proposal is that adding a decay constant to boundary modes in $d$-dimensional topological insulators and superconductors is topologically equivalent to attaching a ($d-1$)-dimensional point-gap topological phase to the boundary. We furthermore establish the proposal from the extended version of the Nielsen-Ninomiya theorem, relating dissipative gapless modes to point-gap topological numbers. From the bulk-boundary correspondence of the point-gap topological phases, the resultant point-gap topological phases exhibit exceptional boundary states or in-gap higher-order non-Hermitian skin effects.

• Received 28 April 2023
• Revised 10 August 2023
• Accepted 29 September 2023

DOI:https://doi.org/10.1103/PhysRevLett.131.256602