Anomalous Hall Effect Arising form Noncollinear Antiferromagnetism: Mn3Ir as an Example

ORAL

Abstract

Ferromagnetic conductors exhibit anomalous contributions to their transverse (Hall) conductivities that cannot be attributed to Lorentz force on electrons from a magnetic field. The anomalous Hall conductivity is often assumed to be proportional to the magnetization, allowing transport measurements to be used in spintronics as a convenient proxy for magnetometry. However, simple symmetry arguments demonstrate that the anomalous Hall effect requires only time-reversal symmetry breaking and spin-orbit coupling, not net magnetization, and we illustrate our ideas by examining a toy model of noncollinear antiferromagnet on a two-dimensional kagome lattice. This is further backed up with a realistic example based on first-principles calculations, predicting that single-crystals of Mn$_3$Ir, a high-temperature antiferromagnet commenly used in spin-valve devices, have large anomalous Hall conductivities. Hua Chen, Qian Niu, and Allan H. MacDonald, arXiv:1309.4041

*Supported by the Welch Foundation, USNSF, and USDOE.

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Authors

  • Hua Chen

    • University of Texas at Austin
    • Department of Physics, The University of Texas at Austin, Austin, TX, 78712
    • The University of Texas at Austin

  • Qian Niu

    • University of Texas at Austin
    • UT Austin
    • Department of Physics, University of Texas at Austin
    • University of Texas at Austin, Austin, Texas 78712, USA
    • The University of Texas at Austin
    • Department of Physics, The University of Texas at Austin, Austin, Texas 78712, USA

  • Allan MacDonald

    • The University of Texas at Austin
    • Department of Physics, University of Texas at Austin, Austin, Texas 78712-1081, USA
    • Department of Physics, The University of Texas at Austin, Austin, TX, 78712
    • Department of Physics, University of Texas at Austin
    • University of Texas at Austin
    • University of Texas at Austin, Austin, Texas 78712, USA
    • UT Austin
    • Department of Physics, The University of Texas at Austin, Austin, Texas 78712, USA