Influence of rhombohedral stacking order in the electrical resistance of bulk and mesoscopic graphite

TL;DR

This study investigates how rhombohedral stacking order affects the electrical resistance of bulk and mesoscopic graphite, revealing contributions from different crystalline phases and their impact on temperature-dependent resistance.

Contribution

It provides a detailed analysis of the influence of stacking order on graphite's electrical resistance, including experimental fits and identification of crystalline phases.

Findings

Rhombohedral and Bernal phases contribute to resistance.

Semiconducting gaps are 110 meV and 38 meV respectively.

Metallic-like interface conduction affects resistance behavior.

Abstract

The electrical, in-plane resistance as a function of temperature $R(T)$ of bulk and mesoscopic thin graphite flakes obtained from the same batch was investigated. Samples thicker than $\sim 30$ nm show metalliclike contribution in a temperature range that increases with the sample thickness, whereas a semiconductinglike behavior was observed for thinner samples. The temperature dependence of the in-plane resistance of all measured samples and several others from literature can be very well explained between 2 K and 1100 K assuming three contributions in parallel: a metalliclike conducting path at the interfaces between crystalline regions, composed of two semiconducting phases, i.e. Bernal and rhombohedral stacking. From the fits of $R(T)$ we obtain a semiconducting energy gap of $110 \pm 20$meV for the rhombohedral and $38\pm 8 $meV for the Bernal phase. The presence of these crystalline phases was confirmed by x-ray diffraction measurements. We review similar experimental data from literature of the last 33 years and two more theoretical models used to fit $R(T)$.