Cyclotron resonance and Faraday rotation in graphite

TL;DR

This paper analytically evaluates the optical conductivity of graphite under strong magnetic fields, explaining resonance peaks and revealing conditions for metal-insulator transitions, with implications for understanding Dirac line excitations.

Contribution

It provides an analytical model for graphite's optical conductivity in quantizing magnetic fields, highlighting the role of Dirac lines and potential doping-induced phase transitions.

Findings

Conductivity peaks explained by electron transitions

Graphite's conductivity approaches graphene's universal value at high frequencies

Possible metal-insulator transition under doping in high magnetic fields

Abstract

The optical conductivity of graphite in quantizing magnetic fields is analytically evaluated for frequencies in the range of 10--300 meV, where the electron relaxation processes can be neglected and the low-energy excitations at the "Dirac lines" are more essential. The conductivity peaks are explained in terms of the electron transitions in graphite. Conductivity calculated per one graphite layer tends on average to the universal conductivity of graphene while the frequency is larger than the Landau spacing. The (semi)metal-insulator transformation is possible under doping in high magnetic fields.