Consecutive Insulator-Metal-Insulator Phase Transitions of Vanadium Dioxide by Hydrogen Doping

TL;DR

This study demonstrates how hydrogen doping induces reversible, consecutive insulator-metal-insulator phase transitions in VO2 films at room temperature, revealing the critical role of electron concentration and orbital occupancy in phase change mechanisms.

Contribution

It uncovers the effect of hydrogen doping on VO2's phase transitions, showing successive insulator-metal-insulator states and elucidating the role of polarized charges and orbital occupancy.

Findings

Hydrogen doping induces reversible phase transitions in VO2.

Successive insulator-metal-insulator phases observed at room temperature.

Polarized charges influence orbital occupancy and electronic properties.

Abstract

We report modulation of a reversible phase transition in VO2 films by hydrogen doping. A metallic phase and a new insulating phase are successively observed at room temperature as the doping concentration increases. It is suggested that the polarized charges from doped hydrogens play an important role. These charges gradually occupy V3d-O2p hybridized orbitals and consequently modulate the filling of the VO2 crystal conduction band-edge states, which eventually evolve into new valence band-edge states. This demonstrates the exceptional sensitivity of VO2 electronic properties to electron concentration and orbital occupancy, providing key information for the phase transition mechanism.