Hall Coefficient of the Intercalated Graphite CaC$_6$ in the Uniaxial CDW Ground State

TL;DR

This paper investigates how magnetic breakdown and quantum interference affect the Hall coefficient in intercalated graphite CaC$_6$ with a reconstructed Fermi surface due to uniaxial charge density wave, revealing unique quantum oscillations.

Contribution

It provides a theoretical analysis of magnetotransport in CaC$_6$, highlighting the impact of magnetic breakdown on Hall coefficient oscillations in a reconstructed Fermi surface.

Findings

Magnetic breakdown causes strong quantum oscillations in the Hall coefficient.

Quantum interference modifies classical magnetoconductivity expressions.

Oscillations differ from standard Shubnikov de Haas effects due to open Fermi surface.

Abstract

We evaluate the Hall coefficient characterising magnetotransport in an intercalated graphite CaC$_6$ with the Fermi surface reconstructed by an uniaxial charge density wave from closed pockets to open sheets. As the typical order parameter, corresponding to the pseudo-gap in electronic spectrum and consequently to spacing between electron trajectories in reciprocal space, is of the order of $10^2$K, magnetic breakdown in strong experimentally achievable fields of the order of 10T is inevitable. The classical expressions for the components of the magnetoconductivity tensor are strongly modified by magnetic field-assisted over-gap tunneling causing quantum interference. Due to magnetic breakdown, all magnetoconductivity components undergo strong quantum oscillations reflected in the Hall coefficient. In their nature, these are different than standard Shubnikov de Haas oscillations which would not appear in a system with an open Fermi surface.