Discovery of a skyrmion that can be manipulated by an external electric field
Electrons are particles characterized by two different physical quantities, i.e. charge and spin. While the only degree of freedom employed in conventional silicon electronics is charge, recently electron spin has also been utilized as a tool for the development of devices with more innovative functions. In some special metallic alloys, electron spins form a vortex-like structure called a skyrmion. Since skyrmions can behave as nanometer-scale particles, they are considered as promising candidates as information carriers in the next generation of computing or memory devices. For this purpose, the discovery of new materials able to host skyrmions as well as the development of skyrmion manipulation methods are in great demand.
Assistant Professor Shinichiro Seki and his colleagues at the University of Tokyo’s Quantum Phase Electronics Center investigated the spin texture of the insulating magnet Cu2OSeO3 using a Lorentz transmission electron microscope, and discovered the formation of skyrmions in insulating materials for the first time. Through dielectric measurements, they have further revealed that skyrmions induce electric polarization (spatially-aligned pairs of positive and negative charge). This indicates that skyrmions in insulators can be manipulated by an external electric field, which causes only negligible heat energy loss. The current discovery provides a new concept in the method of electron manipulation, and will contribute to the development of next generation of high energy efficiency computing or memory devices.
S. Seki, X. Z. Yu, S. Ishiwata, Y. Tokura,
“Observation of Skyrmions in a Multiferroic Material”,
Science Vol. 336 no. 6078 pp. 198-201 doi: 10.1126/science.1214143