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

[19p-Z14-1] [Young Scientist Presentation Award Speech] Quantum transport evidence of Weyl fermions in a high-quality ferromagnetic perovskite oxide SrRuO₃ thin film

〇Kosuke Takiguchi^1,2, Yuki K Wakabayashi¹, Hiroshi Irie¹, Yoshiharu Krockenberger¹, Takuma Otsuka³, Hiroshi Sawada³, Sergey A. Nikolaev^4,5, Hena Das^4,5, Masaaki Tanaka^2,6, Yoshitaka Taniyasu¹, Hideki Yamamoto¹ (1.NTT BRL, 2.EEIS, Univ. of Tokyo, 3.NTT CSL, 4.MSL, Tokyo Tech., 5.WRHI, Tokyo Tech., 6.CSRN, Univ. of Tokyo)

Keywords:perovskite oxide, topological material, Weyl semimetal

SrRuO₃, a 4d ferromagnetic metal with the perovskite structure, provides a promising opportunity to seek the existence of Weyl fermions in magnetic materials. We observed direct quantum transport evidence of Weyl fermions on a ultra-high quality SrRuO₃ thin films grown by machine-leanirng assisted molecular beam epitaxy: (i) unsaturated linear positive magnetoresistance (MR), (ii) chiral-anomaly-induced negative MR, (iii) π Berry phase accumulated along cyclotron orbits, (iv) light cyclotron masses, and (v) high quantum mobility of about 10000 cm²/Vs. Also, our first principles calculations found the Weyl nodes near the Fermi level which can reproduce our experimental results well. Therefore, our experimental data and calculations establish SrRuO₃ as a magnetic Weyl semimetal.