Theoretical Study on the Metal-Insulator Control by Atomic Adsorption onto the MXene Dioxide Ti₂CO₂

Abstract

On the basis of first-principles calculations within the density functional theory, we report possibility of control of metal-insulator property by ion adsorption on Ti₂C MXene dioxide, Ti₂CO₂. Our simulation reveals that Ti₂CO₂ is insulating with indirect band-gap of 0.44 eV, while atomic adsorption of any of H, Li, and Na onto it turned it to be metallic. This metal-insulator change may be applicable to switching devices with high on/off ratio and small energy consumption by controlling ionic movements like ion batteries.