Intrinsic physics in magnetic Weyl semimetal SrRuO3 films addressed by machine-learning-assisted molecular beam epitaxy

Abstract

Abstract The itinerant 4d ferromagnetic perovskite SrRuO3 [bulk Curie temperature (T C) = 165 K] has been studied extensively for many decades because of the unique nature of its ferromagnetism, metallicity, chemical stability, and compatibility with other perovskite-structured oxides. Recently, SrRuO3 has been gathering renewed interest as a magnetic Weyl semimetal and a two-dimensional ferromagnetic system. Ultra-high-quality SrRuO3 film growth techniques, combining oxide molecular beam epitaxy technology and a statistical machine learning method, have revealed new physics and physical properties of SrRuO3 as a magnetic Weyl semimetal, such as quantum transport of Weyl fermions and high-mobility two-dimensional carriers from surface Fermi arcs. This review summarizes the methods of growing ultra-high-quality SrRuO3 films and the novel physics found in them. In addition, progress in crystal structure analyses and the electrical and magnetic properties of SrRuO3 over the last decade will also be discussed.