Sharp Contrasts in Low-Energy Quasiparticle Dynamics of Graphite between Brillouin ZoneKandHPoints

Abstract

The low-energy quasiparticle (QP) dynamics of graphite are governed by a coupling with the E(2g) longitudinal optical phonon of omega(LO) approximately 200 meV, which is found to dramatically depend on the electronic band dispersion epsilon(k). A discontinuity of the QP linewidth develops near omega(LO) for a linear band with a quadratic band top [near the Brillouin zone (BZ) K point], while it disappears for a pure linear band (near the BZ H point). It is also found that the effective electron-phonon coupling near the K point is stronger than near the H point by more than 50%. This finding makes possible a consistent understanding of recent angle-resolved photoemission observations near the K point.

High-resolution angle-resolved photoemission studies of quasiparticle dynamics in graphite

“…We also note that Σ ′ ep is not affected seriously by the detailed shape of Σ ′′ ep near ω = 0 because Σ ′′ ep increases linearly. This aspect was considered in calculating Σ ′′ ep for K and H points 9 . It was argued that Σ ′′ ep is somewhat different at K and H because the band structure at K is parabolic near the Fermi level while that at H is linear.…”

“…On the theoretical side, very little work can be found on the EPC in semi-metals even though it has been well developed and widely studied in metallic systems 6 . Only very recently has some theoretical models for graphene appeared 7,8,9 . On the experimental side, electron lifetime was measured only for the energies larger than the maximum phonon energy of graphite (∼ 200 meV) 10,11,12 in the 2PPE experiments 2,3 .…”

Observation of inhibited electron-ion coupling in strongly heated graphite

“…It has the highest electron mobility and thermal conductivity of any bulk material, and both features also suggest unique behaviour in the electron-ion coupling. A large body of work exists studying this electron-ion energy transfer in both graphite [2][3][4][5][6][7][8][9] and graphene [10][11][12] . However, these measured values strongly disagree with current theoretical models 3 .…”