  We report on angle-dependent measurements of the sheet resistances and Hall
coefficients of electron liquids in SmTiO3/SrTiO3/SmTiO3 quantum well
structures, which were grown by molecular beam epitaxy on (001) DyScO3. We
compare their transport properties with those of similar structures grown on
LSAT [(La0.3Sr0.7)(Al0.65Ta0.35)O3]. On DyScO3, planar defects normal to the
quantum wells lead to a strong in-plane anisotropy in the transport properties.
This allows for quantifying the role of defects in transport. In particular, we
investigate differences in the longitudinal and Hall scattering rates, which is
a non-Fermi liquid phenomenon known as lifetime separation. The residuals in
both the longitudinal resistance and Hall angle were found to depend on the
relative orientations of the transport direction to the planar defects. The
Hall angle exhibited a robust T2 temperature dependence along all directions,
whereas no simple power law could describe the temperature dependence of the
longitudinal resistances. Remarkably, the degree of the carrier lifetime
separation, as manifested in the distinctly different temperature dependences
and diverging residuals near a critical quantum well thickness, was completely
insensitive to disorder. The results allow for a clear distinction between
disorder-induced contributions to the transport and intrinsic, non-Fermi liquid
phenomena, which includes the lifetime separation.
