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Corundum Insulating Phases in Highly Ti-doped V2O3 Nanocrystals
Y. Ishiwata*, T. Maruyama, S. Otsuru, T. Tsukahara, H. Ishii, Y.-F. Liao, K.-D. Tsuei, M. Imamura, K. Takahashi, Y. Inagaki, T. Kawae, T. Kida, S. Suehiro, M. Nantoh, and K. Ishibashi
2020/04/01
Doping V2O3 with Ti stabilizes the corundum paramagnetic metallic phase and restricts the transition to the monoclinic antiferromagnetic insulating phase at lower temperatures. In this study, we investigated the dependence of phase stability on Ti concentration for V2O3 nanocrystals as small as 20 nm. Ti doping of several percent induces a high-temperature insulating phase preserving the magnetic transition without the crystal symmetry change. The emergence of the insulating phases, which are peculiar to this crystal size, can be attributed to the enhancement of the on-site Coulomb interaction U and increased mixing between a1g and egπ states accompanied by characteristic lattice parameter changes in the high Ti doping region.