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arXiv · 1711.02460

Spin-Orbit Coupling and Magnetic Anisotropy in Iron-Based Superconductors

Daniel D. Scherer·Brian M. Andersen
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Abstract

We determine theoretically the effect of spin-orbit coupling on the magnetic excitation spectrum of itinerant multi-orbital systems, with specific application to iron-based superconductors. Our microscopic model includes a realistic ten-band kinetic Hamiltonian, atomic spin-orbit coupling, and multi-orbital Hubbard interactions. Our results highlight the remarkable variability of the resulting magnetic anisotropy despite constant spin-orbit coupling. At the same time, the magnetic anisotropy exhibits robust universal behavior upon changes in the bandstructure corresponding to different materials of iron-based superconductors. A natural explanation of the observed universality emerges when considering optimal nesting as a resonance phenomenon. Our theory is also of relevance to other itinerant system with spin-orbit coupling and nesting tendencies in the bandstructure.

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Daniel D. Scherer, Brian M. Andersen. 2017-11-07. Spin-Orbit Coupling and Magnetic Anisotropy in Iron-Based Superconductors. https://doi.org/10.1103/physrevlett.121.037205

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