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Visualizing Uniaxial-strain Manipulation of Antiferromagnetic Domains in Fe1+YTe Using a Spin-polarized Scanning Tunneling Microscope
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Tunable Magnon Weyl Points in Ferromagnetic Pyrochlores
Alexander Mook1, Jürgen Henk2, Ingrid Mertig1,2
1Max-Planck-Institut für Mikrostrukturphysik, D-06120 Halle (Saale), Germany.
Physical Review Letters
|October 22, 2016
Summary
Magnons in ferromagnetic pyrochlores exhibit Weyl points, which are topologically protected crossings. These create magnon arcs on surfaces, analogous to electronic Weyl semimetals, and are tunable with magnetic fields.
Area of Science:
- Condensed matter physics
- Topological materials science
- Quantum magnetism
Background:
- Ferromagnetic pyrochlores are three-dimensional magnetic materials.
- Topological insulators exhibit unique surface states.
- Dzyaloshinskii-Moriya interaction introduces non-collinear magnetic structures.
Purpose of the Study:
- To investigate the topological properties of magnons in ferromagnetic pyrochlores.
- To explore the role of Dzyaloshinskii-Moriya interaction in magnon dispersion.
- To identify tunable topological features in these materials.
Main Methods:
- Theoretical analysis of magnon dispersion relations.
- Application of symmetry analysis to identify topological invariants.
- Investigation of surface states and their topological characteristics.
Main Results:
- Dispersion relations reveal Weyl points in magnon spectra.
- Magnon Weyl points are topologically nontrivial crossings with opposite charges.
- Surface projections exhibit magnon arcs, similar to Fermi arcs in electronic Weyl semimetals.
- Weyl point positions are tunable via external magnetic fields, including rotation and out-of-plane tilting.
Conclusions:
- Ferromagnetic pyrochlores host topological magnons with Weyl points.
- Magnon arcs provide experimental signatures of topological nontriviality.
- External magnetic fields offer a powerful tool to control topological magnon states.
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