Skyrmion Lattice in a Doped Semiconductor

TL;DR

This study uses small angle neutron scattering to identify a skyrmion lattice phase in doped Fe_{1-x}Co_{x}Si, demonstrating that skyrmions can exist in strongly doped semiconductors and expanding the known materials hosting such magnetic structures.

Contribution

It provides the first evidence of a skyrmion lattice in a doped semiconductor, showing its stability and characteristics in Fe_{1-x}Co_{x}Si.

Findings

Skyrmion lattice observed in Fe_{1-x}Co_{x}Si via SANS.

The skyrmion phase is highly hysteretic and spans a wide temperature range.

Fe_{1-x}Co_{x}Si is the second known material with a skyrmion lattice after MnSi.

Abstract

We report a comprehensive small angle neutron scattering study (SANS) of the magnetic phase diagram of the doped semiconductor Fe_{1-x}Co_{x}Si for x=0.2 and 0.25. For magnetic field parallel to the neutron beam we observe a six-fold intensity pattern under field-cooling, which identifies the A-phase of Fe_{1-x}Co_{x}Si as a skyrmion lattice. The regime of the skyrmion lattice is highly hysteretic and extents over a wide temperature range, consistent with the site disorder of the Fe and Co atoms. Our study identifies Fe_{1-x}Co_{x}Si is a second material after MnSi in which a skyrmion lattice forms and establishes that skyrmion lattices may also occur in strongly doped semiconductors.