  High $ZT$ value and large Seebeck coefficient have been reported in the
nanostructured Fe-doped Si-Ge alloys. In this work, the large Seebeck
coefficient in Fe-doped Si-Ge systems is qualitatively reproduced from the
computed electronic density of states, where a hybrid functional, HSE06, is
used for an exchange-correlation functional, as well as a special quasi-random
structure (SQS) for a disordered atomic configuration. Furthermore, by
replacing Fe with other transition metals, such as Mn, Co, Ni, Cu, Zn, and Au,
a better dopant that produces a larger Seebeck coefficient in Si-Ge alloy
systems is explored.
