On the Relation between Interband Scattering and the "Metallic Phase" of Two Dimensional Holes in GaAs/AlGaAs

TL;DR

This study investigates how interband scattering influences the metallic behavior of two-dimensional holes in GaAs/AlGaAs, revealing that inelastic interband scattering activated by temperature explains the resistance increase, with acoustic plasmons potentially mediating this process.

Contribution

It provides a detailed analysis of interband scattering rates and their temperature dependence, linking them to the metallic phase in 2D hole systems and proposing a role for acoustic plasmons.

Findings

Inelastic interband scattering rates depend on temperature with an Arrhenius law.

The metallic behavior is due to activation of interband scattering.

Acoustic plasmons may mediate Coulomb scattering leading to observed effects.

Abstract

The "metallic" regime of holes in GaAs/AlGaAs heterostructures corresponds to densities where two splitted heavy hole bands exist at a zero magnetic field. Using Landau fan diagrams and weak field magnetoresistance curves we extract the carrier density in each band and the interband scattering rates. The measured inelastic rates depend Arrheniusly on temperature with an activation energy similar to that characterizing the longitudinal resistance. The "metallic" characteristics, namely, the resistance increase with temperature, is hence traced to the activation of inelastic interband scattering. The data are used to extract the bands dispersion relations as well as the two particle-hole excitation continua. It is then argued that acoustic plasmon mediated Coulomb scattering might be responsible for the Arrhenius dependence on temperature. The absence of standard Coulomb scattering characterized by a power law dependence upon temperature is pointed out.