Magnetic topological insulators enable the quantum anomalous Hall effect with edge states for lossless charge transport. These edge states are hosted by a magnetic band gap at the Dirac point which, however, never been observed directly by angle-resolved photoelectron spectroscopy (ARPES) despite its importance for the achievable operation temperature of devices. Here, ARPES is employed to demonstrate a magnetic gap at the Dirac point of Mn-doped Bi2Te3 films . The gap is 32 meV wide  and thus twice as large as predicted by density functional theory . We discuss reasons for this discrepancy. Moreover, the control system Mn-doped Bi2Se3 does not show a magnetic gap .
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