Magnetophonon spectroscopy of Dirac fermion scattering by transverse and longitudinal acoustic phonons in graphene
journal contributionposted on 15.10.2019, 08:45 authored by Mark GreenawayMark Greenaway, R Krishna Kumar, P Kumaravadivel, A.K. Geim, L Eaves
Recently observed magnetophonon resonances in the magnetoresistance of graphene are investigated using the Kubo formalism. This analysis provides a quantitative fit to the magnetophonon resonances over a wide range of carrier densities. It demonstrates the predominance of carrier scattering by low-energy transverse acoustic (TA) mode phonons: the magnetophonon resonance amplitude is significantly stronger for the TA modes than for the longitudinal acoustic (LA) modes. We demonstrate that the LA and TA phonon speeds and the electron-phonon coupling strengths determined from the magnetophonon resonance measurements also provide an excellent fit to the measured dependence of the resistivity at zero magnetic field over a temperature range of 4–150 K. A semiclassical description of magnetophonon resonance in graphene is shown to provide a simple physical explanation for the dependence of the magneto-oscillation period on carrier density. The correspondence between the quantum calculation and the semiclassical model is discussed.
Engineering and Physical Sciences Research Council (EPSRC),
the Royal Society
Lloyd’s Register Foundation