Atomic scale visualization of topological spin textures in the chiral magnet MnGe

TL;DR

This study uses spin polarized scanning tunneling microscopy to visualize and analyze topological spin textures in MnGe thin films at the atomic scale, revealing domain structures, their manipulation, and correlation with surface strain.

Contribution

It provides the first atomic-scale imaging of topological magnetic textures in MnGe and links surface structures with three-dimensional magnetic configurations and controllable topological states.

Findings

Identification of helical stripe domains and domain walls in MnGe

Discovery of target-like and pi-like topological spin textures

Reversible manipulation of spin textures via current, voltage, and magnetic field

Abstract

Spin polarized scanning tunneling microscopy is used to directly image topological magnetic textures in thin films of MnGe, and to correlate the magnetism with structure probed at the atomic-scale. Our images indicate helical stripe domains, each characterized by a single wavevector Q, and their associated helimagnetic domain walls, in contrast to the 3Q magnetic state seen in the bulk. Combining our surface measurements with micromagnetic modeling, we deduce the three-dimensional orientation of the helical wavevectors and gain detailed understanding of the structure of individual domain walls and their intersections. We find that three helical domains meet in two distinct ways to produce either a "target-like" or a "pi-like" topological spin texture, and correlate these with local strain on the surface. We further show that the target-like texture can be reversibly manipulated through either current/voltage pulsing or applied magnetic field, a promising step toward future applications.