Controlled epitaxial growth and oxygen excess doping of the Mott insulator LaTiO₃

Here we demonstrate that thin films of the prototypical Mott insulator LaTiO₃ grown by pulsed laser deposition under oxygen atmosphere are readily tuned by excess oxygen doping across the line of the band-filling controlled Mott transition in the electronic phase diagram [1]. The detected insulator to metal transition is characterized by a strong change in resistivity of several orders of magnitude. The use of suitable substrates and capping layers to inhibit oxygen diffusion facilitates full control of the oxygen content and renders the films stable against exposure to ambient conditions. These achievements represent a significant advancement in control and tuning of the electronic properties of LaTiO_3+x thin films making it a promising channel material in future Mottronic devices.

[1] P. Scheiderer, M.Schmitt, J. Gabel, M. Zapf, M. Stübinger, P.Schütz, L. Dudy, C. Schlueter, T.-L.
Lee, M.Sing, and R. Claessen, Adv. Mater. 30, 1706708 (2018)