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

Soonbeom Seo,Shi-Zeng Lin,Sean M Thomas,Joe D Thompson,Satoru Hayami,Filip Ronning,Ying Su,Eric D Bauer,Priscila F S Rosa

doi:10.1038/s42005-021-00558-8

Soonbeom Seo, Shi-Zeng Lin + Show 7 more

Open Access

https://doi.org/10.1038/s42005-021-00558-8

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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.

Highlights

Unusual magnetic textures can be stabilized in f-electron materials due to the interplay between competing magnetic interactions, complex Fermi surfaces, and crystalline anisotropy
Though the field-dependent magnetic phases are different and the sign of the two peaks are reversed between 1 and 5 T, the smaller peaks at higher temperature are always more sensitive to [001] strain than the largest peaks at lower temperature. These results indicate that in CeAuSb2 (i) the higher transition temperature at Ts is consistent with a structural transition, as structural transitions are naively expected to be more sensitive to lattice distortions caused by uniaxial strain than magnetic transitions, and (ii) the coupled phase transitions are preserved at high field, namely the zero-field coupled structural–magnetic transition survives in the 2Q phase
The temperature- and field-dependent experiments in CeAuSb2 indicate that the former factor is dominant in the 2Q phase above Hc1

Summary

Introduction

Unusual magnetic textures can be stabilized in f-electron materials due to the interplay between competing magnetic interactions, complex Fermi surfaces, and crystalline anisotropy. One example is tetragonal CeAuSb2, in which a conventional single-Q (1Q) magnetic order, as well as a more exotic double-Q (2Q) magnetic order are stabilized as a function of magnetic fields (H) applied along the c-axis In both phases, magnetic moments point along the c-axis due to the strong Ising spin anisotropy. The stripe pattern with twofold rotational symmetry in the ab-plane has been recently shown to be associated with a nematic state—an electronic state that breaks the rotational symmetry of the underlying lattice, but not its translational symmetry[22] This nematic state, which sets in just above TN, is accompanied by a structural transition that is strongly coupled to the 1Q stripe phase below Hc1 The field dependence of the resistivity in CeAuSb2 remains poorly understood, and whether it is better described by a localized or itinerant 4f-electron picture remains controversial[20,24]

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