KAIST: "Vortex Spin Can Form Without Special Physical Conditions"

A team of Korean researchers has proposed a new theory stating that "skyrmions can form solely through the fundamental physics of magnets, without requiring special physical conditions."

Skyrmions are structures within magnets where electron spins are arranged in a vortex-like pattern. Research in this field is active because if skyrmions can be freely created and controlled, it could lead to the development of next-generation, ultra-low-power information devices. This new theory is significant as it demonstrates the potential for the development of such next-generation information devices.

Asymmetric spin configuration image generated by the interaction between lattice and spins. KAIST (AI generated)

On March 19, KAIST announced that the research team led by Professor Kim Segwon from the Department of Physics had proposed a new theory suggesting that a vortex-shaped magnetic structure can be formed simply through the coupling of magnetism (magnetic order) and lattice (elasticity).

The core of the theory is that a vortex-shaped magnetic structure can naturally form inside a magnet solely due to the interaction between spin (the tiny magnetic property possessed by electrons) and lattice deformation (the minute twisting of atomic arrangements).

Skyrmions that appear within magnetic materials are extremely small and highly stable, making them strong candidates for use in ultra-high-density, low-power information devices. However, the prevailing consensus had been that certain physical conditions—such as structural asymmetry in the crystal or strong spin-orbit coupling—were necessary to form such skyrmion structures.

In contrast, the research team theoretically demonstrated that a structure in which skyrmions and anti-skyrmions alternately arrange themselves can self-assemble solely through "magnetoelastic coupling," which naturally occurs in most magnetic materials.

Magnetoelastic coupling is a fundamental physical property in which magnetism (spins) and the deformation of atomic arrangements influence each other, and it is present in nearly all magnetic substances.

(From left) Professor Kim Segwon, Dr. Ko Kyungchun. KAIST

The team confirmed that when this coupling becomes sufficiently strong, the ground state of magnetism—previously aligned in a particular direction—can spontaneously become unstable and transition into a new vortex-like order.

In particular, they proposed a new mechanism in which the tilting of spins and lattice distortion occur simultaneously during this process, forming a "chiral spin structure" in which skyrmions and anti-skyrmions are alternately arranged.

Professor Kim stated, "Through this research, we have confirmed that magnetic structures like skyrmions can form even without special interactions. Most importantly, this study is meaningful because it demonstrates the possibility of realizing such structures even in two-dimensional magnetic materials, which are extremely thin, at the atomic thickness level."

Meanwhile, Dr. Ko Kyungchun participated as the first author of the research. The results were published on February 11 in the international physics journal Physical Review Letters.

This content was produced with the assistance of AI translation services.