Violation of Kohler's rule by the magnetoresistance of a quasi-two-dimensional organic metal

TL;DR

This study investigates the magnetoresistance behavior of a quasi-two-dimensional organic metal, revealing violations of Kohler's rule across various temperatures and fields, indicating complex transport mechanisms beyond simple semiclassical models.

Contribution

It demonstrates that Kohler's rule does not hold for this material, suggesting the need for alternative explanations of magnetotransport in layered conductors.

Findings

Magnetoresistance shows stronger temperature dependence than zero-field resistance.

Kohler's rule is violated across all tested temperatures and magnetic fields.

Possible explanations include incoherent interlayer transport and deviations from semiclassical theory.

Abstract

The interlayer magnetoresistance of the quasi-two-dimensional metal $\alpha$-(BEDT-TTF)$_2$KHg(SCN)$_4$ is considered. In the temperature range from 0.5 to 10 K and for fields up to 10 tesla the magnetoresistance has a stronger temperature dependence than the zero-field resistance. Consequently Kohler's rule is not obeyed for any range of temperatures or fields. This means that the magnetoresistance cannot be described in terms of semiclassical transport on a single Fermi surface with a single scattering time. Possible explanations for the violations of Kohler's rule are considered, both within the framework of semi-classical transport theory and involving incoherent interlayer transport. The issues considered are similar to those raised by the magnetotransport of the cuprate superconductors.