1205.3936 (Jian-Min Zhang et al.)

Tailoring Magnetic Doping in the Topological Insulator Bi$_{2}$Se$_{3}$    [PDF]

Jian-Min Zhang, Wenguang Zhu, Ying Zhang, Di Xiao, Yugui Yao

We theoretically investigated the possibility of establishing ferromagnetism in the topological insulator Bi$_{2}$Se$_{3}$ via magnetic doping of 3d transition metal elements. The formation energies, charge states, band structures, and magnetic properties of doped Bi$_{2}$Se$_{3}$ are studied using first-principles calculations within density functional theory. Our results show that Bi substitutional sites are energetically more favorable than interstitial sites for single impurities. Detailed electronic structure analysis reveals that Cr and Fe doped materials are still insulating in the bulk but the intrinsic band gap of Bi$_{2}$Se$_{3}$ is substantially reduced due to the strong hybridization between the 3d states of the dopants and the $p$ states of the neighboring Se atoms. The calculated magnetic coupling suggests that Cr doped Bi$_{2}$Se$_{3}$ is possible to be both ferromagnetic and insulating, while Fe doped Bi$_{2}$Se$_{3}$ tends to be weakly anti-ferromagnetic.

View original: http://arxiv.org/abs/1205.3936