Impact of Short-Range Scattering on the Metallic Transport of Strongly Correlated 2D Holes in GaAs Quantum Wells

TL;DR

This study investigates how short-range disorder affects the metallic transport properties of strongly correlated 2D holes in GaAs quantum wells, revealing that increased short-range disorder suppresses metallic behavior.

Contribution

It demonstrates the distinct impact of short-range versus long-range disorder on 2D metallicity in strongly correlated hole systems, using controlled variation of interface roughness and alloy scattering.

Findings

Increasing Al fraction x suppresses 2D metallicity.

Short-range disorder reduces the temperature scale of metallic behavior.

Long-range disorder effects differ from short-range in 2D transport.

Abstract

Understanding the non-monotonic behavior in the temperature dependent resistance, R(T), of strongly correlated two-dimensional (2D) carriers in clean semiconductors has been a central issue in the studies of 2D metallic states and metal-insulator-transitions. We have studied the transport of high mobility 2D holes in 20nm wide GaAs quantum wells (QWs) with varying short-range disorder strength by changing the Al fraction x in the Al_xGa_{1-x}As barrier. Via varying the short range interface roughness and alloy scattering, it is observed that increasing x suppresses both the strength and characteristic temperature scale of the 2D metallicity, pointing to the distinct role of short-range versus long-range disorder in the 2D metallic transport in this correlated 2D hole system with interaction parameter r_s~ 20.