Metal-insulator transitions in epitaxial LaVO$_3$ and LaTiO$_3$ films

We have demonstrated that epitaxial films of LaVO3 and LaTiO3 can exhibit metallicity though their bulk counterparts are Mott insulators. When LaTiO3 films are compressively strained on SrTiO3 substrates, we observe metallicity that is attributed largely to epitaxial strain-induced electronic structure modifications and secondarily to interface electronic reconstruction at the LaTiO3/SrTiO3 interface. However, when LaVO3 films are compressively strained on SrTiO3 substrates, the observed metallicity is primarily attributed to interface effects. Signatures of weak localization are observed at low temperature in LaVO3 films in the temperature, film thickness, as well as magnetic field dependence of the magnetoresistance.