Unconventional Hall effect in pnictides from interband interactions

TL;DR

This paper investigates how interband interactions in multiband pnictides lead to unconventional Hall effect behavior, explaining experimental puzzles and extending understanding of transport in complex materials.

Contribution

It introduces a framework beyond Boltzmann theory showing that vertex corrections cause quasiparticle currents to reflect the majority carriers, affecting Hall coefficient predictions.

Findings

Unconventional Hall effect observed in pnictides.

Vertex corrections significantly alter transport predictions.

Temperature dependence of Hall coefficient explained.

Abstract

We calculate the Hall transport in a multiband systems with a dominant interband interaction between carriers having electron and hole character. We show that this situation gives rise to an unconventional scenario, beyond the Boltzmann theory, where the quasiparticle currents dressed by vertex corrections acquire the character of the majority carriers. This leads to a larger (positive or negative) Hall coefficient than what expected on the basis of the carrier balance, with a marked temperature dependence. Our results explain the puzzling measurements in pnictides and they provide a more general framework for transport properties in multiband materials.