Adsorption effect on the formation of conductive path in defective TiO2: ab initio calculations

Abstract

Although the metal/TiO 2 /metal junctions providing resistive switching properties have attracted lots of attention in recent decades, revealing the atomic-nature of conductive path in TiO 2 active layer remains a critical challenge. Here the effects of metal adsorption on defective TiO 2 (1 1 0) surface are theoretically investigated via ab initio calculations. The dependence of the conductive path on the adsorption of Ti/Zr/Cu/Pt/O atoms above a lattice Ti-ion in (1 1 0) plane and at 〈1 1 0〉 direction of the defective TiO 2 (0 0 1) surface are compared. It is found that Ti adsorptions in both sites give larger contributions to the presence of conductive path with more stability and larger transport coefficients at Fermi level, whereas the O adsorptions at both sites fail to produce conductive path. Moreover, the adsorptions of Zr/Cu/Pt atoms reduce the existence possibility of conductive path, especially absorbed above the lattice Ti-ion at 〈1 1 0〉 direction. Thus, it is helpful to clarify the interaction of the metal electrode and oxide layer in resistive random access memory.