Revealing the role of high-valence elementary substitution in the hydrogen-induced Mottronic transitions of vanadium dioxide

Zhou, X.*; 福谷 克之; 他9名*

Zhou, X.*; Fukutani, Katsuyuki; 9 of others*

Electron-doping Mottronics within correlated vanadium dioxide opens up a paradigm to abruptly regulate the Mottronic phase transitions via adjusting the -orbital occupancy and configuration. Nevertheless, the potential impact of high-valence elementary substitution in the hydrogen-associated Mottronic transitions of VO is yet unclear. Herein, we demonstrate the role of high-valence elementary substitution in regulating the hydrogen-triggered Mottronic transitions of VO, assisted by quantitative hydrogen analysis using the nuclear reaction analysis. Substituting vanadium with a high-valence transitional metal within doped-VO largely reduces the hydrogen incorporation compared to the intrinsic VO under the low temperature hydrogenation process. Therefore, in contrast to hydrogen-induced electron localization of intrinsic VO upon low-temperature hydrogenation, only the hydrogen-triggered metallic state is observed within the hydrogen-associated phase diagram of WVO, as further probed by the near-edge X-ray absorption fine structure analysis and X-ray photoelectron spectroscopy. The present work reveals the overlooked role associated with the donor substitutions that largely influences the competitive equilibrium between the two rival hydrogen-induced Mottronic transitions within VO toward either the metallic or the highly insulating phase.