Definition of skyrmion

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Photonics Dictionary

skyrmion: A skyrmion is a topologically stable, vortex-like configuration of spins in a magnetic material. These configurations are characterized by a swirling pattern where the direction of the magnetic moments (spins) forms a continuous and non-repeating structure. Skyrmions are named after the British physicist Tony Skyrme, who first theorized their existence in the 1960s in the context of nuclear physics.

Topology: Skyrmions are topologically protected, meaning their configuration is stable and cannot be easily transformed into a uniform state without a significant amount of energy. This topological stability makes them robust against perturbations.

Magnetic texture: In a skyrmion, the spins rotate smoothly from one direction to another, forming a vortex-like structure. The spins at the center of a skyrmion point in one direction (e.g., up), while those at the periphery point in the opposite direction (e.g., down), with spins in between gradually rotating.

Skyrmion number: This is a topological invariant that quantifies the "twist" in the spin configuration. It is an integer representing the number of times the spin configuration wraps around the sphere.

Applications: Due to their stability and small size (often just a few nanometers in diameter), skyrmions are of interest for potential applications in spintronics, data storage, and quantum computing. They can be manipulated with low electric currents, making them promising for energy-efficient information technologies.

Formation and control: Skyrmions can form in certain magnetic materials under specific conditions, such as the presence of Dzyaloshinskii-Moriya interaction (an interaction that favors non-collinear spin arrangements), external magnetic fields, or temperature changes. They can be created, moved, and annihilated using electric currents, magnetic fields, or thermal gradients.

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