[14a-K502-1~8] 6.3 Oxide electronics

11:15 AM - 11:30 AM JST(2:15 AM - 2:30 AM UTC)

[14a-K502-7] Instability of Ligand Hole Magnetic Metallic State in Unusual High-Valent Perovskite Oxide Superlattices

〇Takuto Soma¹, Yuki Honda¹, Kodai Niitsu², Yasuhide Mochizuki¹, Soungmin Bae³, Kohei Yoshimatsu¹, Hiroshi Kumigashira^4,5, Akira Ohtomo¹ (1.Science Tokyo, Dept. Chem. Sci. Eng., 2.NIMS, 3.Tohoku Univ. IMR, 4.Tohoku Univ. IMRAM, 5.KEK, IMSS)

Keywords:

unusual high valence,ligand hole,artificial superlattice

In complex oxides such as SrFeO3 and LaNiO3, unusual high valence states, such as Fe4+ and Ni3+, which are not attainable in simple oxides, can be stabilized. In these unusual high valence states, the energy levels of the transition metal 3d and the oxygen 2p orbitals are in close proximity, resulting in strong covalent bonding, with holes also present at the oxygen sites (ligand holes). This phenomenon leads to strong metal-ligand interactions and generates diverse magnetic metallic states. Furthermore, the significance of this interaction has been emphasized in the context of high-temperature superconductivity in cuprates and recently discovered nickel oxides, suggesting that the formation of two-dimensional ligand holes can facilitate electronic states analogous to those observed in high-temperature superconductors. To date, attempts have been made utilizing artificial superlattices composed of conduction layers with unusual high oxidation states and insulating block layers; however, these efforts have consistently resulted in transitions to insulating states, thereby impeding the advancement of research. Therefore, in this study, we investigated the changes in electronic states by fabricating artificial superlattices of ligand hole metals exclusively, a novel approach that has not been previously explored.