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Oxygen interstitials and vacancies in liquid ion gated VO2 films: site determination and migration pathстатья
- Авторы: Mosheni K., Kumar N., Altendorf S., Stepanyuk V.S., Bazhanov D.I., Felici R., Meyerheim H.L., Parkin S.S.P
- Журнал: В печати (submitted)
- Год издания: 2019
- Аннотация: VO2 is an archetype correlated transition metal oxide which exhibits a temperature controlled metal to insulator transition at T_C ~ 340K. Recent experiments have shown that high electric fields mediated by ionic liquid gating leads to the suppression of the phase transition in thin films (~10nm), making them metallic to temperatures as low as 5K. The metallic and insulating phase, which can be reversibly transformed into each other by gating and back-gating, are related to the tetragonal rutile (R) and the monoclinic structure, respectively. The transition from the monoclinic to the R phase goes in parallel with a giant expansion of the c-lattice constant by almost 3% which is ten times larger than the temperature induced phase transition and opposite in sign. It has been suggested that ionic liquid gating leads to the formation of oxygen vacancies within the film structure, which remain stable after the gate voltage is switched off, but their density (~0.3 atomic percent) is too low to account for the large number of electron carriers formed (~1 per VO$_{2}$ per formula unit).
- Добавил в систему: Бажанов Дмитрий Игоревич