Mn induced ferromagnetism and modulated topological surface states in Bi2Te3

The ferromagnetism and topological surface states manipulated by manganese in topological insulator Bi2Te3 are investigated by means of first-principles calculations. Our results indicate that substitution Mn for Bi can induce spin-polarized hole states with a total magnetic moments of 4.0 mu(B), and sufficient hole carrier density is required to obtain sustained magnetization. The obvious gap at the Dirac point coinciding with sharp surface state appears as Mn doped into Bi2Te3 because the magnetic interactions break the time reversal symmetry. The study paves a way to explore topological magnetoelectric effect and spintronic device applications. (C) 2011 American Institute of Physics. [doi:10.1063/1.3601020]