  We discuss the Seebeck coefficient and the Hall mobility of electrons
confined in narrow SrTiO3 quantum wells as a function of the three-dimensional
carrier density and temperature. The quantum wells contain a fixed sheet
carrier density of ~ 7x10^14 cm^-2 and their thickness is varied. At high
temperatures, both properties exhibit apparent Fermi liquid behavior. In
particular, the Seebeck coefficient increases nearly linearly with temperature
(T) when phonon drag contributions are minimized, while the mobility decreases
proportional to T^2. Furthermore, the Seebeck coefficient scales inversely with
the Fermi energy (decreasing quantum well thickness). In contrast, the
transport scattering rate is independent of the Fermi energy, which is
inconsistent with a Fermi liquid. At low temperatures, the Seebeck coefficient
deviates from the linear temperature dependence for those electron liquids that
exhibit a correlation-induced pseudogap, indicating a change in the energy
dependence of the scattering rate. The implications for describing transport in
strongly correlated materials are discussed.
