Faugeras C, Berciaud S, Leszczynski P, Henni Y, Nogajewski K, Orlita M, Taniguchi T, Watanabe K, Forsythe C, Kim P, Jalil R, Geim A K, Basko D M, Potemski M
Laboratoire National des Champs Magnétiques Intenses, CNRS, (UJF, UPS, INSA), BP 166, 38042 Grenoble, Cedex 9, France.
Institut de Physique et Chimie des Matériaux de Strasbourg and NIE, UMR 7504, Université de Strasbourg and CNRS, BP43, 67034 Strasbourg, Cedex 2, France.
Phys Rev Lett. 2015 Mar 27;114(12):126804. doi: 10.1103/PhysRevLett.114.126804.
We present magneto-Raman scattering studies of electronic inter-Landau level excitations in quasineutral graphene samples with different strengths of Coulomb interaction. The band velocity associated with these excitations is found to depend on the dielectric environment, on the index of Landau level involved, and to vary as a function of the magnetic field. This contradicts the single-particle picture of noninteracting massless Dirac electrons but is accounted for by theory when the effect of electron-electron interaction is taken into account. Raman active, zero-momentum inter-Landau level excitations in graphene are sensitive to electron-electron interactions due to the nonapplicability of the Kohn theorem in this system, with a clearly nonparabolic dispersion relation.
我们展示了对具有不同库仑相互作用强度的准中性石墨烯样品中电子朗道能级间激发的磁拉曼散射研究。发现与这些激发相关的能带速度取决于介电环境、所涉及的朗道能级指数，并随磁场变化。这与无相互作用的无质量狄拉克电子的单粒子图像相矛盾，但当考虑电子 - 电子相互作用的影响时，理论可以对此进行解释。由于科恩定理在该系统中不适用，石墨烯中拉曼活性的零动量朗道能级间激发对电子 - 电子相互作用敏感，具有明显的非抛物线色散关系。
