Interaction Induced Magnetotransport in a 2D Dirac-Heavy Hole Hybrid Band System

TL;DR

This study reveals how electron-electron interactions in a hybrid 2D Dirac-parabolic band system significantly affect magnetotransport properties, validating a theoretical model involving massive-massless fermion interactions.

Contribution

It provides experimental validation for a theoretical model describing magnetotransport in hybrid Dirac and parabolic band systems.

Findings

Significant corrections to magnetoresistivity and Hall effect at high temperatures.

Transport data agree with a model of massive-massless fermion interactions.

Collisions between particles with different dispersions govern magnetotransport.

Abstract

While electron-electron (e-e) interactions are known to influence resistivity in non-Galilean invariant two-dimensional (2D) systems, their effect on magnetotransport is not fully understood. Conventional models for simple bands often predict a vanishing magnetoresistivity from e-e interactions alone. In this work, we investigate magnetotransport in a gapless 6.3 nm HgTe quantum well, a hybrid 2D band system that hosts coexisting holes with both linear (Dirac-like) and parabolic energy bands. Focusing on the high temperature regime where particle-particle collisions dominate scattering, we observe significant corrections to both the magnetoresistivity and the Hall effect. The high temperature transport coefficients are in good agreement with the theoretical model describing transport in massive-massless fermion mixtures governed by a frictional mechanism and intervalley scattering. Our findings provide strong experimental validation for this theoretical framework, demonstrating that collisions between particles with different dispersions are a key mechanism governing magnetotransport in hybrid band semimetals.