  Interfacing the quantum anomalous Hall insulator with a conventional
superconductor is known to be a promising manner for realizing a topological
superconductor, which has been continuously pursued for years. Such a proximity
route depends to a great extent on the control of the delicate interfacial
coupling of the two constituents. However, a recent experiment reported the
failure to reproduce such a topological superconductor, which is ascribed to
the negligence of the electrical short by the superconductor in the theoretical
proposal. Here, we reproduce this topological superconductor with attention to
the interface control. The resulted conductance matrix under a wide magnetic
field range agrees with the fingerprint of this topological superconductor.
This allows us to develop a phase diagram that unveils three regions
parameterized by various coupling limits, which not only supports the
feasibility to fabricate the topological superconductor by proximity but also
fully explains the origin of the previous debate. The present work provides a
comprehensible guide on fabricating the topological superconductor.
