DFT + U Simulation of the Ti4O7-TiO2 Interface

Abstract

The formation of conducting channels of Ti4O7 inside TiO2-based memristors is believed to be the origin for the change in electric resistivity of these devices. While the properties of the bulk materials are reasonably well known, the interface between them has not been studied up to now, mostly because of their different crystalline structures. In this work, we present a way to match the interfaces between TiO2 and Ti4O7 and subsequently the band offset between these materials is obtained from density-functional-theory-based calculations. The results show that, while the valence band is located at the Ti4O7, the conduction band is found at the TiO2 structure, resulting in a type-II interface. In this case, the Ti4O7 acts as a donor to the TiO2 matrix.