Electric transport in three-dimensional Skyrmion/monopole crystal

TL;DR

This paper theoretically investigates the electric transport properties of a three-dimensional topologically nontrivial spin texture composed of Skyrmion strings and monopole pairs, revealing novel magnetoresistivity effects and phase transitions.

Contribution

It introduces a detailed finite temperature Green's function analysis of electron transport in a complex 3D spin texture, connecting topological features with observable electrical phenomena.

Findings

Identification of a topological phase transition in MnGe

Prediction of a novel magnetoresistivity effect

Correlation between monopole dynamics and resistivity behavior

Abstract

We study theoretically the transport properties of a three-dimensional spin texture made from three orthogonal helices, which is essentially a lattice of monopole-antimonopole pairs connected by Skyrmion strings. This spin structure is proposed for MnGe based on the neutron scattering experiment as well as the Lorentz transmission electron microscopy observation. Equipped with a sophisticated spectral analysis method, we adopt finite temperature Green's function technique to calculate the longitudinal dc electric transport in such system. We consider conduction electrons interacting with spin waves of the topologically nontrivial spin texture, wherein fluctuations of monopolar emergent magnetic field enter. We study in detail the behavior of electric resistivity under the influence of temperature, external magnetic field and a characteristic monopole motion, especially a novel magnetoresistivity effect describing the latest experimental observations in MnGe, wherein a topological phase transition signifying strong correlation is identified.