Modulation of VO2 Metal-Insulator Transition by Ferroelectric HfO2 Gate Insulator

Ferroelectric gating of functional materials has often suffered because ferroelectric materials are poor insulators. In this study, the recently reported ferroelectric HfO2, a large band-gap oxide with excellent insulating properties, is exploited for electrostatically gating the archetypical metal-insulator transition material, VO2. By protecting the meta-stable ferroelectric phase from deterioration, the ferroelectric gating is successfully demonstrated with an ultra-thin VO2 channel in the back-gate geometry. The observed modulation of the VO2 channel conductivity is originated from the ferroelectric polarization reversal in the HfO2 gate insulator combined with the VO2 metal-insulator transition. These results demonstrate the significant potential of ferroelectric HfO2 for electrostatically controlling the state of matter for both fundamental research and device application.