Anomalous metallic states at magnetic interfaces in an antiferromagnetic topological insulator candidate DyPtBi with ferroquadrupolar order

Kentaro Ueda; Hiraku Saito; Zen Ogame; Isao Ishii; Ruo Hibino; Tatsuya Yanagisawa; Shinichi Itoh; Taro Nakajima; Yoshinori Tokura

arXiv · 2608.22260

Anomalous metallic states at magnetic interfaces in an antiferromagnetic topological insulator candidate DyPtBi with ferroquadrupolar order

Kentaro Ueda·Hiraku Saito·Zen Ogame·Isao Ishii·Ruo Hibino·Tatsuya Yanagisawa·Shinichi Itoh·Taro Nakajima·Yoshinori Tokura

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Abstract

Antiferromagnetic topological insulators provide a fertile platform where symmetry-breaking magnetic order is intertwined with topological electronic states. In particular, magnetic domain walls have attracted much attention, as they can be easily controlled by external fields as in general magnets, and moreover, host nontrivial electronic states distinct from those in bulks and sample surfaces. Here, we report a new antiferromagnetic topological insulator candidate DyPtBi, which hosts conductive magnetic domain walls controllable by uniaxial stress and magnetic field. We find that the resistivity exhibits abrupt increase upon the magnetic and structural phase transition. Concomitantly, the transverse ultrasonic mode shows remarkable softening of 6 %, indicating that the Dy 4f ferroquadrupolar order plays a vital role in the phase transition. Furthermore, we reveal by neutron experiments that applying compressive uniaxial stress aligns the magnetic domain state, leading to the strong resistivity enhancement of 14 % while eliminating the conductive magnetic domain walls. These findings demonstrate that DyPtBi exhibits topological electronic states entangled with multipolar degrees of freedom, providing a promising route for in situ control of topological properties.

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Kentaro Ueda, Hiraku Saito, Zen Ogame, Isao Ishii, Ruo Hibino, Tatsuya Yanagisawa, Shinichi Itoh, Taro Nakajima, Yoshinori Tokura. 2026-08-23. Anomalous metallic states at magnetic interfaces in an antiferromagnetic topological insulator candidate DyPtBi with ferroquadrupolar order. https://arxiv.org/abs/2608.22260

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