Real-space observation of short-period cubic lattice of skyrmions in MnGe

TL;DR

This paper reports the first real-space observation of a three-dimensional cubic lattice of skyrmions in MnGe with a very short period of about 3 nm, revealing a high-density skyrmion configuration and its potential for spintronic applications.

Contribution

It provides the first direct real-space imaging of a cubic skyrmion lattice in MnGe, demonstrating a very short period and high skyrmion density, advancing understanding of 3D skyrmion structures.

Findings

Observation of a cubic skyrmion lattice in MnGe

Skyrmion lattice period of approximately 3 nm

Direct imaging of skyrmions with atomic lattice fringes

Abstract

Emergent phenomena and functions arising from topological electron-spin textures in real space or momentum space are attracting growing interest for new concept of states of matter as well as for possible applications to spintronics. One such example is a magnetic skyrmion, a topologically stable nanoscale spin vortex structure characterized by a topological index. Real-space regular arrays of skyrmions are described by combination of multi-directional spin helixes. Nanoscale configurations and characteristics of the two-dimensional skyrmion hexagonal-lattice have been revealed extensively by real-space observations. Other three-dimensional forms of skyrmion lattices, such as a cubic-lattice of skyrmions, are also anticipated to exist, yet their direct observations remain elusive. Here we report real-space observations of spin configurations of the skyrmion cubic-lattice in MnGe with a very short period (~3 nm) and hence endowed with the largest skyrmion number density. The skyrmion lattices parallel to the {100} atomic lattices are directly observed using Lorentz transmission electron microscopes (Lorentz TEMs). It enables the first simultaneous observation of magnetic skyrmions and underlying atomic-lattice fringes. These results indicate the emergence of skyrmion-antiskyrmion lattice in MnGe, which is a source of emergent electromagnetic responses and will open a possibility of controlling few-nanometer scale skyrmion lattices through atomic lattice modulations.