Chirality induced anomalous-Hall effect in helical spin crystals

TL;DR

This paper explores how topologically nontrivial spin textures in helical spin crystals, like those in MnSi under pressure, induce an anomalous Hall effect with unique magnetic field dependence.

Contribution

It introduces the concept that skyrmion density in helical spin crystals leads to a topological Hall effect, expanding understanding of magneto-transport in such materials.

Findings

Topological Hall effect arises from skyrmion density in spin textures.

Unusual field dependence of the Hall effect is predicted.

Application to MnSi under pressure explains experimental observations.

Abstract

Under pressure, the itinerant helimagnet MnSi displays unusual magnetic properties. We have previously discussed a BCC helical spin crystal as a promising starting point for describing the high pressure phenomenology. This state has topologically nontrivial configurations of the magnetization field. Here we note the consequences for magneto-transport that arise generally from such spin textures. In particular a skyrmion density induced `topological' Hall effect, with unusual field dependence, is described.