CQM - Center for Quantum Materials

Novel phenomena in the Mott insulator Ca2RuO4 under non-equilibrium conditions

by Prof. Yoshiteru Maeno (Department of Physics, Kyoto University, Japan)

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The Mott insulator is considered as an electron “solid” frozen due to strong electron correlations. It has a potential to become a good metal if the electron solid melts by suitable stimuli. In this talk, we will describe novel phenomena we found in the layered ruthenium oxide Ca2RuO4, for which non-equilibrium conditions introduced by electric field and current trigger and maintain the charge “liquid” state down to low temperatures [1]. When the electric current is not very large, the Mott gap can be tuned to the critical region of disappearance. We will discuss how the partial Mott-gap closing leads to novel transport and magnetic behavior. This work is done also in collaboration with C. Sow, S. Yonezawa, S. Kitamura, Kuroki, and T. Oka. [1] “Electric-field-induced metal maintained by current of the Mott insulator Ca2RuO4”, F. Nakamura, M. Sakaki, Y. Yamanaka, S. Tamaru, T. Suzuki, and Y. Maeno, Sci. Rep. 3, 2536 (2013).