Electronic anisotropy and rotational symmetry breaking at a Weyl semimetal/spin ice interface.

Wu, Tsung-Chi; Chang, Yueqing; Wu, Ang-Kun; Terilli, Michael; Wen, Fangdi; Kareev, Mikhail; Choi, Eun Sang; Graf, David et al. · Sci Adv · 2025

basic_science · Level V

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Abstract

In magnetic pyrochlore materials, the interplay of spin-orbit coupling, electronic correlations, and geometrical frustration gives rise to exotic quantum phases, including topological semimetals and spin ice. While these phases have been observed in isolation, the interface-driven phenomena emerging from their interaction have never been realized previously. Here, we report on the discovery of interfacial electronic anisotropy and rotational symmetry breaking at a heterostructure consisting of the Weyl semimetal Eu<sub>2</sub>Ir<sub>2</sub>O<sub>7</sub> and spin ice Dy<sub>2</sub>Ti<sub>2</sub>O<sub>7</sub>. Subjected to magnetic fields, we unveil a sixfold anisotropic transport response that is theoretically accounted by a Kondo-coupled heterointerface, where the spin ice's field-tuned magnetism induces electron scattering in the Weyl semimetal's topological Fermi-arc states. Furthermore, at elevated magnetic fields, we reveal a twofold anisotropic response indicative of the emergence of a symmetry-broken many-body state. This discovery showcases the potential of pyrochlore frustrated magnet/topological semimetal heterostructures in search of emergent interfacial phenomena.