Synthesis and Electronic Order in Strongly Correlated Vanadate Thin Films

Mott insulators open a window into a variety of intriguing phenomena from unconventional superconductivity to colossal magnetoresistance. Stoichiometric thin films of Mott insulator LaVO₃ (LVO) and strongly correlated metal SrVO₃ (SVO) have been notoriously difficult to produce due to V atoms forming undesired secondary phases, even under low oxygen conditions. Using molecular beam epitaxy (MBE), we were able to achieve growth conditions necessary to stabilize phase-pure thin films of La_1-xSr_xVO₃ (LSVO) with x ranging from 0 to 1. Ultra low oxygen partial pressures of 5×10^-8 torr, accessible by MBE, enabled the study of oxidation effects on the growth of LVO and SVO. The dependence of electronic behaviors on the Sr-doping concentration x was explored for both LSVO random alloy films and (LVO)_m(SVO)_n ordered superlattices. The contrast in electronic transport measurements between random alloy films and equivalently doped superlattices reveals emergent correlated phenomena upon the introduction of ordering.