Electron-electron correlation in graphite

TL;DR

This study investigates electron-electron interactions in graphite, showing that advanced calculations including correlations match experimental data and highlight the importance of electron interactions in understanding graphite's electronic properties.

Contribution

The paper demonstrates that GW approximation calculations accurately describe graphite's electronic structure, revealing the significance of electron correlations beyond standard density-functional theory.

Findings

GW calculations agree with ARPES data near the Fermi level

Density-functional theory underestimates band slopes and trigonal warping

Electron correlation plays a crucial role in graphite's electronic behavior

Abstract

The full three dimensional dispersion of the pi-bands, Fermi velocities and effective masses are measured with angle resolved photoemission spectroscopy and compared to first-principles calculations. The band structure by density-functional theory strongly underestimates the slope of the bands and the trigonal warping effect. Including electron-electron calculation on the level of the GW approximation, however, yields remarkable agreement in the vicinity of the Fermi level. This demonstrates the breakdown of the independent electron picture in semi-metallic graphite and points towards a pronounced role of electron correlation for the interpretation of transport experiments and double-resonant Raman scattering for a wide range of carbon based materials.