Numerical study of the electronic state and transport properties in a chiral soliton lattice

Chiral magnets often show interesting properties associated with their peculiar spin structures. A typical example is a chiral soliton lattice (CSL), which was found in a monoaxial chiral magnets CrNb₃S₆ [1] and Yb(Ni_1-xCu_x)₃Al₉ [2]. These compounds show a helical spin spiral at zero field, and turn into the CSL in a magnetic field perpendicular to the helical axis. To clarify the electronic and transport properties in the CSL, it is crucial to take into account itinerant electrons; nevertheless, most of the previous studies were focused on localized spin models. Here, we investigate a minimal itinerant electron model, a one-dimensional Kondo lattice model with the Dzyaloshinskii-Moriya interaction, by Monte Carlo simulation and variational calculations. We show that the system exhibits nonlinear negative magnetoresistance in the CSL, which is closely related to the soliton density [3]. We also find that the periodicity of CSL can be locked at commensurate values dictated by the Fermi wave number, which suggests the possibility of spontaneous formation of the CSL even at zero field.

[1] Y. Togawa et al., J. Phys. Soc. Jpn. 85, 112001 (2016).
[2] T. Matsumura et al., J. Phys. Soc. Jpn. 86, 124702 (2017).
[3] S. Okumura, Y. Kato, and Y. Motome, J. Phys. Soc. Jpn. 86, 063701 (2017).