Electronic, magnetic and optical properties of β-Ti3O5 and λ-Ti3O5: A density functional study

Ti3O5 is one of the most promising materials for information storage due to the metal–semiconductor phase transition between β-Ti3O5 and λ-Ti3O5. β-Ti3O5 is a semiconductor while λ-Ti3O5 is metallic. The electronic, magnetic and optical properties of β-Ti3O5 and λ-Ti3O5 are investigated using density functional theory. The electronic interactions are described within the local LSDA+U formalism, where on-site coulomb correction is applied on the 3d orbital of Ti atoms. The calculated energy gap of 0.15 eV of β-Ti3O5 agrees with experimental result when Ueff = 5 eV. β-Ti3O5 is a direct semiconductor with magnetic moment of 0.89 μB per β-Ti3O5 molecular (one molecular contains 3 Ti atoms and 5 O atoms), whereas λ-Ti3O5 exhibits half-metal property with magnetic moment of 1.82 μB per molecular. The optical properties of Ti3O5 are calculated for the imaginary part and real part of the dielectric functions and the result shows that the main differences in absorption, reflectivity, energy-loss function and refractive index exist in the visible spectrum, which makes it a potential material for optical memory device.