Ti_nO_(2n-1) Magneli phases studied using density functional theory

摘要

Defects in the rutile TiO_2 structures have been extensively studied, but the intrinsic defects of the oxygen-deficient Ti_nO_(2n-1) phases have not been given the same amount of consideration. Those structures, known as Magneli phases, are characterized by the presence of ordered planes of oxygen vacancies, also known as shear planes, and it has been shown that they form conducting channels inside TiO-based memristor devices. Memristors are excellent candidates for a new generation of memory devices in the electronics industry. In this paper we present density-functional-theory-based electronic structure calculations for Ti_nO_(2n-1) Magneli structures using PBESol+U (0 ≤ U ≤ 5 eV) and Heyd-Scuseria-Ernzerhof functionals, showing that intrinsic defects present in these structures are responsible for the appearance of states inside the band gap, which can act as intrinsic dopants for the enhanced conductivity of TiO_2 memristive devices.