The electrical, in-plane resistance as a function of temperature $R\left(T\right)$ 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 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 $R\left(T\right)$ 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 $R\left(T\right)$.

• Received 21 March 2016
• Revised 4 August 2016

DOI:https://doi.org/10.1103/PhysRevB.95.045308