Magnetic Field Induced Coherence-Incoherence Crossover in the Interlayer Conductivity of a Layered Organic Metal

TL;DR

This paper investigates how magnetic fields induce a transition from coherent to incoherent interlayer transport in a layered organic metal, revealing two parallel conduction channels and proposing a model for the incoherent component.

Contribution

It introduces a model explaining the incoherent interlayer conductivity and its temperature dependence in layered organic metals under magnetic fields.

Findings

Observation of a crossover from classical to anomalous magnetoresistance behavior.

Identification of two parallel conduction channels in interlayer transport.

Proposal of a simple model for incoherent conductivity with metallic temperature dependence.

Abstract

The angle-dependent interlayer magnetoresistance of the layered organic metal $\alpha$-(BEDT-TTF)$_2$KHg(SCN)$_4$ is found to undergo a dramatic change from the classical conventional behavior at low magnetic fields to an anomalous one at high fields. This field-induced crossover and its dependence on the sample purity and temperature imply the existence of two parallel channels in the interlayer transport: a classical Boltzmann conductivity $\sigma_{c}$ and an incoherent channel $\sigma_{i}$. We propose a simple model for $\sigma_{i}$ explaining its metallic temperature dependence and low sensitivity to the inplane field component.