Ye, F , Chinese Acad Sci, Grad Univ, Coll Mat Sci & Optoelect Technol, Beijing 100049, Peoples R China
部门归属:
[Ye, F] Chinese Acad Sci, Grad Univ, Coll Mat Sci & Optoelect Technol, Beijing 100049, Peoples R China; [Ye, F; Zhai, H] Tsinghua Univ, Inst Adv Study, Beijing 100084, Peoples R China; [Ding, GH] Shanghai Jiao Tong Univ, Dept Phys, Shanghai 200240, Peoples R China; [Su, ZB] Chinese Acad Sci, Inst Theoret Phys, Beijing 100089, Peoples R China
英文摘要:
The surface state of a topological insulator dubbed as helical metal is a unique metallic system, which exhibits one single Dirac cone and spin-momentum locking. We show that the behaviors of magnetic impurities embedded in this kind of surface states manifest the uniqueness of helical metals among other conventional Dirac materials such as graphene. We find there is a significant Dzyaloshinskii-Moriya (DM) term among the effective interactions between impurity spins mediated by the conduction electrons. For a chain of impurity spins, we show that such a DM interaction gives rise to a single-handed spin helix state, the handedness of which is locked with the sign of the Fermi velocity of the emergent Dirac fermions. We also point out that the polarization of impurity spins can be controlled via electric voltage for dilute magnetic-impurity concentration. Copyright (C) EPLA, 2010
