Electrical resistance in thecdirection of graphite

Abstract

The c-axis resistivity (p, ) and its temperature dependence of highly oriented pyrolytic graphite have been studied in connection with the characteristic stacking-fault structure. In order to account for the observations, the pioneering theory of Ono on the tunneling conduction through the stacking-fault planes is reformulated using the concept of effective fault spacing. It is proposed further to add two mechanisms to the Ono theory; one is interlayer charge transfer through the impurity-assisted hopping of carriers similar to that previously considered for graphite intercalation compounds, and the other is thermal excitation of carriers across the low potential barrier formed on each fault plane. All the data have been satisfactorily reproduced by the curve fitting based on the formula consisting of these three conduction components. Also, the change of p, in the presence of high pressure is pointed out to be qualitatively explainable in terms of the tunneling associated with the pressure dependence of Slonczewski-Weiss band parameters.

Spatial extent of a Landauer residual-resistivity dipole in graphene quantified by scanning tunnelling potentiometry

“…The monolayer sheet is continuously connected to the upper bilayer sheet. As known from multilayer graphene and graphite, this upper bilayer sheet is connected to the lower bilayer sheet via a significantly higher interlayer resistivity compared with the inplane resistivity 21,22 . In addition to the higher c-axis resistivity, the electron density is reduced in the upper layer due to distancedependent buffer-layer doping 23,24 and therefore its in-plane resistance also is increased 17 .…”

Field-induced metal-insulator transition in thec-axis resistivity of graphite

“…The T −dependence of ρ c in HOPG has been interpreted [6] in terms of a semiclassical model with parameters like the carrier density n(T ), the stacking-fault spacing l and the potential barrier formed on the plane of stacking disorder ∆E. The increase of ρ c with T at T < 100 K was attributed to an interlayer transfer of carriers which provides the mixing of the c-axis and in-plane transport.…”

“…The increase of ρ c with T at T < 100 K was attributed to an interlayer transfer of carriers which provides the mixing of the c-axis and in-plane transport. It was further speculated that the interaction of the carriers with phonons on the planes determines the T −dependence [6]. We note first that according to the model [6] and from the comparison of the absolute values of ρ c of our samples, sample 2 should have an extremely large stacking-fault density.…”

“…It was further speculated that the interaction of the carriers with phonons on the planes determines the T −dependence [6]. We note first that according to the model [6] and from the comparison of the absolute values of ρ c of our samples, sample 2 should have an extremely large stacking-fault density. This is at odd with x-ray diffraction results that indicate that this kind of lattice defects is absent in high quality HOPG [21].…”

Conductivity of multiwall carbon nanotubes: Role of multiple shells and defects

“…perpendicular to the layers spreads from 4.3 10 −5 Ωm to 6.7 10 −5 Ωm [112,113], depending strongly on the quality of the crystal. Even highly oriented pyrolytic graphite (HOPG) shows a volume resistivity up to 100 times higher along the c-axis than single crystals [113].…”