Strong single-ion anisotropy and anisotropic interactions of magnetic adatoms induced by topological surface states

ORAL

Abstract

The nature of the magnetism brought about by Fe adatoms on the surface of the topological insulator Bi$_{\mathrm{2}}$Se$_{\mathrm{3}}$ was examined in terms of density functional calculations. The Fe adatoms exhibit strong easy-axis magnetic anisotropy in the dilute adsorption limit due to the topological surface states (TSS). The spin exchange J between the Fe adatoms follows a Ruderman-Kittel-Kasuya-Yosida behavior with substantial anisotropy, and the Dzyaloshinskii-Moriya interaction between them is quite strong with \textbar D/J\textbar\ $\approx $ 0.3 under the mediation by the TSS, and can be further raised to 0.6 by an external electric field. The apparent single-ion anisotropy of a Fe adatom is indispensable in determining the spin orientation.

–

Authors

  • Zheng-Lu Li

    Departmenf of Physics, Fudan University, Key Laboratory of Computational Physical Sciences (MOE), State Key Laboratory of Surface Physics, and Dept of Physics, Fudan University, Shanghai

  • Ji-Hui Yang

    Departmenf of Physics, Fudan University, Key Laboratory of Computational Physical Sciences (MOE), State Key Laboratory of Surface Physics, and Dept of Physics, Fudan University, Shanghai

  • Guohong Chen

    Departmenf of Physics, Fudan University

  • M.-H. Whangbo

    Department of Chemistry, North Carolina State University, Department of Chemistry, North Carolina State University, Raleigh, North Carolina 27695-8204, USA

  • Hongjun Xiang

    Fudan University, Departmenf of Physics, Fudan University, Key Laboratory of Computational Physical Sciences (MOE), State Key Laboratory of Surface Physics, and Dept of Physics, Fudan University, Shanghai

  • Xingao Gong

    Fudan University, Departmenf of Physics, Fudan University, Fudan Univerisity, Key Laboratory of Computational Physical Sciences (MOE), State Key Laboratory of Surface Physics, and Dept of Physics, Fudan University, Shanghai