  Magnetic topological insulators such as Cr-doped (Bi,Sb)2Te3 provide a
platform for the realization of versatile time-reversal symmetry-breaking
physics. By constructing heterostructures with N\'eel order in an
antiferromagnetic CrSb and magnetic topological order in Cr-doped (Bi,Sb)2Te3,
we realize emergent interfacial magnetic phenomena which can be tailored
through artificial structural engineering. Through deliberate geometrical
design of heterostructures and superlattices, we demonstrate the use of
antiferromagnetic exchange coupling in manipulating the magnetic properties of
the topological surface massive Dirac fermions. This work provides a new
framework on integrating topological insulators with antiferromagnetic
materials and unveils new avenues towards dissipationless topological
antiferromagnetic spintronics.
