Magnetoresistance in two-component systems

TL;DR

This paper predicts a linear magnetoresistance effect in two-component electron-hole systems at charge neutrality, driven by boundary effects and relevant for materials like semimetals and topological insulators.

Contribution

It introduces a theoretical framework explaining linear magnetoresistance in finite-size, two-component systems at charge neutrality, emphasizing boundary effects and recombination length.

Findings

Linear magnetoresistance occurs in finite samples at charge neutrality.

Boundary regions dominate in narrow samples at strong magnetic fields.

The effect is relevant for semimetals and topological insulators.

Abstract

Two-component systems with equal concentrations of electrons and holes exhibit non-saturating, linear magnetoresistance in classically strong magnetic fields. The effect is predicted to occur in finite-size samples at charge neutrality in both disorder- and interaction-dominated regimes. The phenomenon originates in the excess quasiparticle density developing near the edges of the sample due to the compensated Hall effect. The size of the boundary region is of the order of the electron-hole recombination length that is inversely proportional to the magnetic field. In narrow samples and at strong enough magnetic fields, the boundary region dominates over the bulk leading to linear magnetoresistance. Our results are relevant for semimetals and narrow-band semiconductors including most of the topological insulators.