  One of the keys to the realization of Quantum Anomalous Hall effect (QAHE) is
long range ferromagnetism, which is only experimentally realized in Cr or V
doped (Bi,Sb)2Te3 system. Both elements are 3d transition metals and 4d
transition metals are found to be ineffective to produce long range
ferromagnetism in Bi2Se3. Still, whether long range ferromagnetism can be
realized by magnetic doping of 4d elements is an open question. Based on
density functional theory calculations, we predict that long range
ferromagnetism can be realized in Mo doped Bi2Te3 and Sb2Te3, which are
semiconducting. The coupling strength is comparable with that of Cr doped
Bi2Te3 and Sb2Te3. Therefore, Mo doped Bi2Te3 and Sb2Te3 or their alloys can be
new systems to realize diluted magnetic semiconductors and QAHE.
