Electronic and optical properties of Ti₂O₃ films

Bulk single crystals of titanium sesquioxide (Ti₂O₃) exhibit a thermally-driven metal-to-insulator transition (MIT) between 400-500 Kelvin without a structural phase transition. It is thought that strong electron-electron correlations and charge density wave order contribute to the MIT. Corundum structured Ti₂O₃ films were successfully grown on sapphire substrates by using pulsed laser deposition. X-ray diffraction, Raman spectroscopy, and atomic force microscopy were employed for the structural characterization of the films. Infrared and optical spectroscopy combined with temperature dependent resistivity measurements provided insight into the optical and electronic properties of the films. We shall present data on the structural, electronic, and optical properties of the Ti₂O₃ films and discuss how substrate-induced strain and the morphology of the films affect these properties when compared to bulk single crystals of Ti₂O₃.