Field-induced multiple metal-insulator crossovers of correlated Dirac electrons of perovskite CaIrO3
R. Yamada, J. Fujioka, Minoru Kawamura, Shiro Sakai, Motoaki Hirayama, Ryotaro Arita, Tatsuya Okawa, Daisuke Hashizume, Takuro Sato, Fumitaka Kagawa, Ryosuke Kurihara, Masashi Tokunaga, Yoshinori Tokura
Abstract
Abstract The interplay between electron correlation and topology of relativistic electrons may lead to a fascinating stage of the research on quantum materials and emergent functions. The emergence of various collective electronic orderings/liquids, which are tunable by external stimuli, is a remarkable feature of correlated electron systems, but has rarely been realized in the topological semimetals with high-mobility relativistic electrons. Here, we report that the correlated Dirac electrons in perovskite CaIrO 3 show unconventional field-induced successive metal–insulator–metal crossovers in the quantum limit accompanying a giant magnetoresistance (MR) with MR ratio of 3500 % (18 T and 1.4 K). In conjunction with the numerical calculation, we propose that the insulating state originates from the collective electronic ordering such as charge/spin density wave promoted by electron correlation, whereas it turns into the quasi-one-dimensional metal at higher fields due to the field-induced reduction of chemical potential, highlighting the highly field-tunable character of correlated Dirac electrons.