Electronic excitations and electron-phonon coupling in bulk graphite through Raman scattering in high magnetic fields

Abstract

We use polarized magneto-Raman scattering to study purely electronic excitations and the electron-phonon coupling in bulk graphite. At a temperature of 4.2 K and in magnetic fields up to 28 T we observe K-point electronic excitations involving Landau bands with ∆|n| = 0 and with ∆|n| = ±2 that can be selected by controlling the angular momentum of the excitation laser and of the scattered light. The magneto-phonon effect involving the E2g optical phonon and K-point inter Landau bands electronic excitations with ∆|n| = ±1 is revealed and analyzed within a model taking into account the full kz dispersion. These polarization resolved results are explained in the frame of the Slonczewski-Weiss-McClure (SWM) model which directly allows to quantify the electron-hole asymmetry.

Rhombohedral Multilayer Graphene: A Magneto-Raman Scattering Study

“…The observed electronic excitation spectrum in magnetic field is composed of a series of features linearly dispersing with increasing magnetic field and of the ERS observed at B = 0, that acquires a fine structure at finite B. The linearly dispersing features, in line with magneto-Raman scattering selection rules in graphene 39 or in graphite, 36 can be attributed to symmetric (Δ|n| = 0, where n is the Landau level index) inter Landau level excitations within the E 0 ±1 bands, and they represent the strongest contribution to the electronic Raman scattering spectrum in magnetic field. Optical-like excitations (Δ|n| = ±1) are not directly seen, but they effectively couple to the G band.…”

Evidence for semiconducting behavior with a narrow band gap of Bernal graphite

“…Therefore, we believe that the intrinsic properties of the single-crystalline graphite regions are not actually seen by this technique. Also other experimental techniques (see, e.g., [38]) would have problems in recognizing an electronic band structure with an energy gap of the order of 40 meV if the carrier density is much larger than the intrinsic one of ideal, defect-free graphite. (c) We may ask about the results on graphite using angle-resolved photoemission spectroscopy (ARPES) published several times in the past.…”

Infrared magnetospectroscopy of graphite in tilted fields

“…Limits of this model have been found, e.g., by revealing the electron-hole asymmetry at the K point of bulk graphite in recent magnetotransmission, 11 magnetoreflection, 14,17 and magneto-Raman studies. 15,16 The full SWM model has to be used in such a case to get a quantitative agreement between experimental data and theory.…”