Orbital Aspects of Electron Correlation in the Metallic Oxide SrVO₃

Electron correlation is responsible for countless interesting condensed matter phenomena. Oxides with electron correlation provide an attractive testbed for many of those, where coupling between the spin, charge and lattice degrees of freedom can be found and tuned. We consider strontium vanadate (SrVO₃) as a simple test case of the Mott-Hubbard type of correlated electronic structure. The material’s (relative) simplicity stems from its d¹ electronic configuration and high-symmetry cubic perovskite structure. Furthermore, SrVO₃ is interesting for being the metallic endmember of compounds exhibiting a filling-controlled metal-insulator transition. Recently, SrVO₃ has shown promise as an earth-abundant transparent conductive oxide (TCO), a crucial element of solar cells and other optoelectronic devices. We harness advanced thin film synthesis techniques via oxide reactive molecular beam epitaxy to fabricate SrVO₃ films with high structural quality, as evidenced by an electronic behavior in the low-defect regime. We combine electronic transport measurements with optical conductivity analysis, bridging between the macroscopic manifestation of the correlation and the band structure. By decoupling the contribution of defects from the electronic transport, we observe the orbital character of the electron correlation in this material. This picture, derived from a simple and clean system, might shed light on other, more complex examples.