Mn-doped silicon nanowires: First-principles calculations

We present first-principles calculation of Mn-doped silicon nanowires. We discuss the energetics of both isolated point defects and Mn dimers, where a different behavior of the magnetization vs doping curve is predicted depending on the type of impurity. As a result of the broadening of the band gap, the range of doping condition that favors the stability of the substitutional Mn defect increases with respect to bulk. We also show that Mn dimers favor ferromagnetic alignment, discussing how the driving force to form aggregates has an essential role to stabilize ferromagnetism in the nanowires. © 2008 The American Physical Society.