Transport properties and quantum oscillation phenomena in correlated CaVO₃ epitaxial thin films

Early transition metal oxides with perovskite structure exhibit enhanced electron correlation, serving as an ideal platform for investigating fundamental transport mechanisms in strongly correlated electron systems. In this thesis, a comprehensive study of the electronic transport properties of epitaxial thin films of orthorhombic CaVO₃ on LaAlO₃ substrates is presented. The films, grown under varying vanadium partial pressures, exhibit distinctly different residual resistivity ratios (RRR), including samples with the highest RRR values reported to date. Temperature- and magnetic field-dependent measurements of the resistivity and Hall effect are performed up to 64 T to characterize the scattering mechanisms governing charge transport in this correlated metal and to establish their connection to the Fermi surface. In films with low defect concentration (RRR > 60) and temperatures below 20 K, the resistivity follows a clear T² dependence, characteristic of Fermi-liquid behavior. Hall measurements reveal evidence for a weak hole contribution at intermediate temperatures 50 < T < 100 K and a dominant contribution of two electron-like carriers for T < 20 K. Furthermore, a large non-saturating linear magnetoresistance (LMR) is observed below 40 K. Its origin may be attributed to multi-carrier transport, anisotropic scattering, or impeded orbital motion. Quantum oscillations in both Hall- and magnetoresistance reveal a 50 T oscillation above 8 T and two high-frequency oscillations at 5000 T and 6000 T above 40 T, from which the effective masses, scattering times, and Dingle temperatures are extracted. It is shown that the T² resistivity and LMR are intrinsic features of high-quality CaVO₃ epitaxial films. A comparison with cubic SrVO₃ epitaxial films highlights the key distinctions between these two correlated perovskite oxide systems, most notably the reduced contribution from the hole-like Fermi surface in CaVO₃.