Temperature-driven changes in the Fermi surface of graphite

TL;DR

This study reveals that the Fermi surface of graphite changes with temperature, affecting carrier density and magnetoresistance anisotropy, which is crucial for understanding semimetal behavior.

Contribution

It provides experimental evidence of temperature-dependent Fermi surface modifications in graphite through magnetotransport measurements.

Findings

Fermi pocket size varies with temperature.

Magnetoresistance obeys an extended Kohler's rule.

Fermi surface anisotropy scales with temperature.

Abstract

We report on temperature-dependent size and anisotropy of the Fermi pockets in graphite revealed by magnetotransport measurements. The magnetoresistances obtained in fields along the c-axis obey an extended Kohler's rule, with the carrier density following prediction of a temperature-dependent Fermi energy, indicating a change in the Fermi pocket size with temperature. The angle-dependent magnetoresistivities at a given temperature exhibit a scaling behavior. The scaling factor that reflects the anisotropy of the Fermi surface is also found to vary with temperature. Our results demonstrate that temperature-driven changes in Fermi surface can be ubiquitous and need to be considered in understanding the temperature-dependent carrier density and magnetoresistance anisotropy in semimetals.