Effect of linear density of states on the quasi-particle dynamics and small electron-phonon coupling in graphite

TL;DR

This study uses ARPES to analyze graphite's electronic structure, revealing a linear density of states near the Fermi level, small electron-phonon coupling, and detailed spectral features.

Contribution

It provides high-quality spectral data on graphite, demonstrating the impact of linear density of states on quasiparticle dynamics and electron-phonon interactions.

Findings

Spectral function shows asymmetric lineshapes explained by band structure and escape depth.

Width of spectral function near K point is proportional to energy, indicating linear density of states.

Electron-phonon coupling constant is bounded at about 0.2, lower than previous estimates.

Abstract

We obtained the spectral function of very high quality natural graphite single crystals using angle resolved photoelectron spectroscopy (ARPES). A clear separation of non-bonding and bonding bands and asymmetric lineshape are observed. The asymmetric lineshapes are well accounted for by the finite photoelectron escape depth and the band structure. The extracted width of the spectral function (inverse of the photohole life time) near the K point is, beyond the maximum phonon energy, approximately proportional to the energy as expected from the linear density of states near the Fermi energy. The upper bound for the electron-phonon coupling constant is about 0.2, a much smaller value than the previously reported one.