Title: In situ Electric Field Skyrmion Creation in Magnetoelectric Cu$_2$OSeO$_3$,
Abstract: Magnetic skyrmions are localized nanometric spin textures with quantized
winding numbers as the topological invariant. Rapidly increasing attention has
been paid to the investigations of skyrmions since their experimental discovery
in 2009, due both to the fundamental properties and the promising potential in
spintronics based applications. However, controlled creation of skyrmions
remains a pivotal challenge towards technological applications. Here, we report
that skyrmions can be created locally by electric field in the magnetoelectric
helimagnet Cu$\mathsf{_2}$OSeO$\mathsf{_3}$. Using Lorentz transmission
electron microscopy, we successfully write skyrmions in situ from a helical
spin background. Our discovery is highly coveted since it implies that
skyrmionics can be integrated into contemporary field effect transistor based
electronic technology, where very low energy dissipation can be achieved, and
hence realizes a large step forward to its practical applications.