Chern Numbers for Spin Models of Transition Metal Nanomagnets

2003/03/26 by C. M. Canali, A. Cehovin, A. H. MacDonald
Chemistry · Materials Science · Physics and Astronomy · #Advanced NMR Techniques and Applications #Magnetic properties of thin films #Magnetism in coordination complexes #cond-mat.mes-hall

paper · pdf · doi:10.1103/physrevlett.91.046805

arxiv created 2003/03/26 · openalex publication_date 2003/07/25 · arxiv updated 2009/11/30 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

We argue that ferromagnetic transition metal nanoparticles with fewer than approximately 100 atoms can be described by an effective Hamiltonian with a single giant spin degree of freedom. The total spin S of the effective Hamiltonian is specified by a Berry curvature Chern number that characterizes the topologically nontrivial dependence of a nanoparticle's many-electron wave function on magnetization orientation. The Berry curvatures and associated Chern numbers have a complex dependence on spin-orbit coupling in the nanoparticle and influence the semiclassical Landau-Liftshitz equations that describe magnetization-orientation dynamics.

Citations

• Magnetic Anisotropy Variations and Non-Equilibrium Tunneling in a Cobalt Nanoparticle
• Homotopy and Quantization in Condensed Matter Physics
• Elementary excitations of ferromagnetic metal nanoparticles
• Holonomy, the Quantum Adiabatic Theorem, and Berry's Phase
• Magnons in real materials from density-functional theory