相关论文: Observation of magneto-phonon resonance of Dirac f…
We report on resonance Raman spectroscopy measurements with excitation photon energy down to 1.16 eV on graphene, to study how low-energy carriers interact with lattice vibrations. Thanks to the excitation energy close to the Dirac point at…
We perform Raman scattering experiments on natural graphite in magnetic fields up to 45 T, observing a series of peaks due to interband electronic excitations over a much broader magnetic field range than previously reported. We also…
The magneto-phonon resonance or MPR occurs in semiconductor materials when the energy spacing between Landau levels is continuously tuned to cross the energy of an optical phonon mode. MPRs have been largely explored in bulk semiconductors,…
The different physical properties of multilayered graphene or graphite relative to single layer graphene result from the Dirac spins symmetry in graphene and the Pauli spin symmetry in graphite. The Dirac symmetry in multilayers of graphene…
The problem of Dirac fermions in graphite subject to a perpendicular magnetic field is studied. We show analytically that the weak inter-layer interaction between the graphene sheets leads to anomalies in the Shubnikov-de Haas and de…
Magneto-Raman scattering experiments from the surface of graphite reveal novel features associated to purely electronic excitations which are observed in addition to phonon-mediated resonances. Graphene-like and graphite domains are…
We report a comprehensive study of the tuning with electric fields of the resonant magneto-exciton optical phonon coupling in gated graphene. For magnetic fields around $B \sim 25$ T which correspond to the range of the fundamental…
By solving two-component spinor equation for massless Dirac Fermions, we show that graphene under a periodic external magnetic field exhibits a unique energy spectrum: At low energies, Dirac Fermions are localized inside the magnetic region…
Electrons in graphene behave like Dirac fermions, permitting phenomena from high energy physics to be studied in a solid state setting. A key question is whether or not these Fermions are critically influenced by Coulomb correlations. We…
Motivated by the results of recent photoemission and tunneling studies, we discuss potential many-body sources of a finite gap in the Dirac fermion spectrum of graphene. Specifically, we focus on the putative Peierls- and Cooper-like…
Our low-temperature magneto-Raman scattering measurements performed on graphene-like locations on the surface of bulk graphite reveal a new series of magneto-phonon resonances involving both K-point and Gamma-point phonons. In particular,…
A deformation of a graphene sheet changes more than the positions of the atoms. In the low-energy Dirac theory it also produces geometric electron-phonon vertices. One of these vertices acts as an emergent phonon gauge field, $\calA_\mu$,…
We describe a peculiar fine structure acquired by the in-plane optical phonon at the Gamma-point in graphene when it is brought into resonance with one of the inter-Landau-level transitions in this material. The effect is most pronounced…
We report the observation of an intense anomalous peak at 1608 cm$^{-1}$ in the Raman spectrum of graphene associated to the presence of chromium nanoparticles in contact with graphene. Bombardment with an electron beam demonstrates that…
We study the effect of a magnetic field on Dirac fermions in graphene subject to a scalar potential oscillating in time. Using the Floquet theory and resonance approximation, we show that the energy spectrum exhibits extra subbands resulted…
We have investigated theoretically the resonance splitting effect of Dirac electrons through graphene superlattices with periodic potentials of square barriers. It is found that each resonance peak in the transmission gap presents…
We study the problem of Dirac fermion confinement in graphene in the presence of a perpendicular magnetic field B. We show, analytically and numerically, that confinement leads to anomalies in the electronic spectrum and to a magnetic field…
Magneto Raman scattering study of the E$_{2g}$ optical phonons in multi-layer epitaxial graphene grown on a carbon face of SiC are presented. At 4.2K in magnetic field up to 33 T, we observe a series of well pronounced avoided crossings…
The behaviour of a Dirac electron in graphene, under magnetic fields which are orthogonal to the layer, is studied. The initial problem is reduced to an equivalent one, where two one-dimensional Schr\"{o}dinger Hamiltonians $H^{\pm}$ are…
Tuning interactions between Dirac states in graphene has attracted enormous interest because it can modify the electronic spectrum of the two-dimensional material, enhance electron correlations, and give rise to novel condensed-matter…