  We investigate proximity effects in a correlated heterostructure of a
two-dimensional Mott insulator (MI) and a topological insulator (TI) by
employing inhomogeneous dynamical mean-field theory. We show that the edge
state of the TI induces strongly renormalized mid-gap states inside the MI
region, which still have a remnant of the helical energy-spectrum. The
penetration of low-energy electrons, which is controlled by the interface
tunneling $V$, largely enhances the electron mass inside the MI and also splits
a single Dirac-cone at edge sites into the spatially-separated two Dirac-cones
in the strong $V$ region.
