  Implementing topological superconductivity (TSC) and Majorana states (MSs) is
one of the most significant and challenging tasks in both fundamental physics
and topological quantum computations. In this work, taking the obstructed
atomic insulator (OAI) Nb3Br8, s-wave superconductor (SC) NbSe2 and
ferromagnetic insulator (FMI) as example, we propose a new setup to realize the
2D chiral TSC and MSs in the OAI/SC/FMI heterostructure, which could avoid the
subband problem effectively and has the advantage of huge Rashba spin-orbit
coupling. As a result, the TSC phase can be stabilized in a wide region of
chemical potential and Zeeman field, and four distinct TSC phases with
superconducting Chern number N= -1, -2, -3, 3 can be achieved. Moreover, a 2D
BdG Hamiltonian based on the triangular lattice of obstructed Wannier charge
centers, combined with the s-wave superconductivity paring and Zeeman field, is
constructed to understand the whole topological phase diagram analytically.
These results expand the application of OAIs and pave a new way to realize the
TSC and MSs with unique advantages.
