Graphite in the bi-layer regime: in-plane transport

TL;DR

This paper investigates the unexpected increase in in-plane resistivity of graphite at high temperatures, attributing it to intervalley scattering caused by high-frequency optical phonons, challenging previous saturation expectations.

Contribution

The study introduces a new theoretical model explaining the temperature-dependent resistivity increase in graphite through intervalley phonon scattering mechanisms.

Findings

Resistivity $ ho_{ab}$ increases significantly between 300 and 900 K.

Intervalley scattering by optical phonons explains the resistivity behavior.

Contradicts previous expectations of resistivity saturation at high temperatures.

Abstract

An interplay between the increase in the number of carriers and the decrease in the scattering time is expected to result in a saturation of the in-plane resistivity, $\rho_{ab}$, in graphite above room temperature. Contrary to this expectation, we observe a pronounced increase in $\rho_{ab}$ in the interval between 300 and 900 K. We provide a theory of this effect based on intervalley scattering of charge carriers by high-frequency, graphene-like optical phonons.