Coherent vs incoherent interlayer transport in layered metals

TL;DR

This study compares the interlayer transport mechanisms in two quasi-2D organic superconductors, revealing coherent transport in one and incoherent in the other through magnetoresistance measurements.

Contribution

It provides experimental evidence distinguishing coherent and incoherent interlayer transport in layered metals using magnetoresistance analysis.

Findings

Coherent interlayer transport confirmed in $$-(BEDT-TTF)$_2$I$_3$ by a peak at 90b0.

Incoherent transport suggested in $eta$''-(BEDT-TTF)$_2$SF$_5$CH$_2$CF$_2$SO$_3$ due to non-metallic behavior.

Different interlayer transport mechanisms are identified in two similar layered metals.

Abstract

The magnetic-field, temperature, and angular dependence of the interlayer magnetoresistance of two different quasi-two-dimensional (2D) organic superconductors is reported. For $\kappa$-(BEDT-TTF)$_2$I$_3$ we find a well-resolved peak in the angle-dependent magnetoresistance at $\Theta = 90^\circ$ (field parallel to the layers). This clear-cut proof for the coherent nature of the interlayer transport is absent for $\beta$''-(BEDT-TTF)$_2$SF$_5$CH$_2$CF$_2$SO$_3$. This and the non-metallic behavior of the magnetoresistance suggest an incoherent quasiparticle motion for the latter 2D metal.