Spin-texture-driven electrical transport in multi-Q antiferromagnets

Abstract

Unusual magnetic textures can be stabilized in f-electron materials due to the interplay between competing magnetic interactions, complex Fermi surfaces, and crystalline anisotropy. Here we investigate CeAuSb2, an f-electron incommensurate antiferromagnet hosting both single-Q and double-Q spin textures as a function of magnetic fields (H) applied along the c axis. Experimentally, we map out the field-temperature phase diagram via electrical resistivity and thermal expansion measurements. Supported by calculations of a Kondo lattice model, we attribute the puzzling magnetoresistance enhancement in the double-Q phase to the localization of the electronic wave functions caused by the incommensurate magnetic texture.

Skyrmion crystals in centrosymmetric triangular magnets under hexagonal and trigonal single-ion anisotropy

“…In addition, the present results give a possibility of realizing further exotic multiple-Q states other than the SkXs, such as the hedgehog lattices [52,53,54,55,56,114,57,115,58,116,59], meron-antimeron crystal [117,60,118,26,61,119], vortex crystal [120,112,121,122,76,123,108,124,109], and bubble state [125,126,127,68,110,111]. Indeed, we found instabilities to-ward the vortex and bubble crystals in the presence of different types of singleion anisotropy, as shown in Figs.…”

“…A similar triple-Q bubble I state has been discussed in the other systems with the dipolar interaction [75] and spin-charge coupling [87]. The tendency where the multiple-Q bubble crystal is stabilized under the uniaxial anisotropy is common to the tetragonal-lattice case [110,111].…”

Skyrmion crystal with integer and fractional skyrmion numbers in a nonsymmorphic lattice structure with the screw axis

“…In addition, the present results provide a potential realization of multiple-Q spin crystals other than the SkX, such as the meron-antimeron [41,[121][122][123][124][125], hedgehog [126][127][128][129][130][131][132][133][134], vortex [114,115,[135][136][137][138][139][140][141], and bubble crystals [62,[142][143][144][145][146], in nonsymmorphic systems with a screw axis. As these spin textures are stabilized by the anisotropic exchange interaction and the multiple-spin interaction, which have not been taken into account in the present model, further exotic spin textures that have never been reported in the single-layer system might be expected in nonsymmorphic systems with layer degrees of freedom.…”

Magnetic field-temperature phase diagrams for multiple-$Q$ magnetic orderings: Exact steepest descent approach to long-range interacting spin systems

“…In addition, the model can be extended to include higher-order contributions. For instance, the four-spin biquadratic interactions ∝ (S Qη •S −Qη ) 2 [49,50,58,63,[72][73][74][75][76][77][78][79] and the six-spin bicubic interactions ∝ {S Q1 • (S Q2 × S Q3 )} 2 [61] have also been considered as the origin of stabilization of multiple-Q magnetic orderings.…”

“…In this case, J Qη in the two-spin interaction part does not have to be positive definite. Furthermore, Method II can deal with the generic form of the Hamiltonian expressed by a function of S α Qη , including multiple-spin interactions, such as the biquadratic ones 50,58,63,[72][73][74][75][76][77][78][79] and the bicubic ones…”