Skyrmions and anomalous Hall effect in a Dzyaloshinskii-Moriya spiral
magnet
Jung Hoon Han, Sungkyunkwan
University
Monte Carlo
simulation study of a classical spin model with Dzyaloshinskii-Moriya
interaction and the spin anisotropy under the magnetic field is presented. We found
a rich phase diagram containing the multiple spin spiral or Skyrme crystal phases
of square, rectangular, and hexagonal symmetries in addition to the spiral spin
state. The Skyrme crystal states are stabilized by a spin anisotropy or a
magnetic field. The Hall conductivity is calculated within the sd model for each of the phases.
Applying a magnetic field induces nonzero uniform chirality and the anomalous
Hall conductivity simultaneously. The field dependence of Hall conductivity is
shown to be a sensitive probe of the underlying magnetic structure. Relevance of
the present results to several recent experiments on MnSi is discussed.