Disorder versus two transport lifetimes in a strongly correlated electron liquid

TL;DR

This study investigates the transport properties of electron liquids in quantum well structures, revealing intrinsic non-Fermi liquid behavior and lifetime separation that are unaffected by disorder, contrasting with defect-induced effects.

Contribution

It provides the first detailed comparison of disorder effects and intrinsic lifetime separation in strongly correlated electron liquids using angle-dependent transport measurements.

Findings

Hall angle shows T^2 temperature dependence across all directions.

Longitudinal resistance does not follow a simple power law with temperature.

Lifetime separation persists independently of disorder effects.

Abstract

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.