[19p-Z14-1~18] 6.3 Oxide electronics

△ [19p-Z14-2] Thickness-dependent quantum transport of Weyl fermions in ultra-high-quality SrRuO₃ thin films

〇Shingo Kaneta^1,2, Yuki K Wakabayashi¹, Yoshiharu Krockenberger¹, Shinobu Ohya^2,3, Masaaki Tanaka^2,4, Yoshitaka Taniyasu¹, Hideki Yamamoto¹ (1.NTT BRL, 2.Univ. of Tokyo, 3.IEI, Univ. of Tokyo, 4.CSRN, Univ. of Tokyo)

Keywords:perovskite oxide, topological material, Weyl semimetal

Emergence of the magnetic Weyl semimetal state has recently been reported in ultrahigh-quality SrRuO₃ thin films, providing a new platform for exploring novel physics related to a pair of Weyl nodes in epitaxial heterostructures. However, there is a dearth of knowledge on the thickness dependence of the quantum transport properties peculiar to the magnetic Weyl semimetal state in it, and hence, we investigated magnetotransport properties of SrRuO₃ with various thicknesses (t = 1–60 nm). Signatures of Weyl fermions—unsaturated linear positive magnetoresistance accompanied with a quantum oscillation having a non-trivial Berry phase—were observed for t ≥ 10 nm. The residual resistivity increases with decreasing film thickness, indicating more disorder near the interface. This thickness-dependent scattering affects magnetic properties as well. These results provide a guideline for designing SrRuO₃-based functional heterostructures in which Weyl fermions play an essential role.