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arXiv · 1411.2070

Spin and Orbital Magnetic Response on the Surface of a Topological Insulator

Yaroslav Tserkovnyak·D. A. Pesin·Daniel Loss
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Abstract

Coupling of the spin and orbital degrees of freedom on the surface of a strong three-dimensional insulator, on the one hand, and textured magnetic configuration in an adjacent ferromagnetic film, on the other, is studied using a combination of transport and thermodynamic considerations. Expressing exchange coupling between the localized magnetic moments and Dirac electrons in terms of the electrons' out-of-plane orbital and spin magnetizations, we relate the thermodynamic properties of a general ferromagnetic spin texture to the physics in the zeroth Landau level. Persistent currents carried by Dirac electrons endow the magnetic texture with a Dzyaloshinski-Moriya interaction, which exhibits a universal scaling form as a function of electron temperature, chemical potential, and the time-reversal symmetry breaking gap. In addition, the orbital motion of electrons establishes a direct magnetoelectric coupling between the unscreened electric field and local magnetic order, which furnishes complex long-ranged interactions within the magnetic film.

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Yaroslav Tserkovnyak, D. A. Pesin, Daniel Loss. 2014-11-08. Spin and Orbital Magnetic Response on the Surface of a Topological Insulator. https://doi.org/10.1103/physrevb.91.041121

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