  With the recent discovery of the quantum anomalous Hall insulator (QAHI),
which exhibits the conductive quantum Hall edge states without external
magnetic field, it becomes possible to create a novel topological
superconductor (SC) by introducing superconductivity into these edge states. In
this case, two distinct topological superconducting phases with one or two
chiral Majorana edge modes were theoretically predicted, characterized by Chern
numbers (N ) of 1 and 2, respectively. We present spectroscopic evidence from
Andreev reflection experiments for the presence of chiral Majorana modes in a
Nb / (Cr0.12Bi0.26Sb0.62)2Te3 heterostructure with distinct signatures
attributed to two different topological superconducting phases. The results are
in qualitatively good agreement with the theoretical predictions.
