title: Observing the quantization of zero mass carriers in graphene.
abstract: Application of a magnetic field to conductors causes the charge carriers to circulate in cyclotron orbits with quantized energies called Landau levels (LLs). These are equally spaced in normal metals and two-dimensional electron gases. In graphene, however, the charge carrier velocity is independent of their energy (like massless photons). Consequently, the LL energies are not equally spaced and include a characteristic zero-energy state (the n = 0 LL). With the use of scanning tunneling spectroscopy of graphene grown on silicon carbide, we directly observed the discrete, non-equally-spaced energy-level spectrum of LLs, including the hallmark zero-energy state of graphene. We also detected characteristic magneto-oscillations in the tunneling conductance and mapped the electrostatic potential of graphene by measuring spatial variations in the energy of the n = 0 LL.
authors.affiliation: School of Physics, Georgia Institute of Technology, Atlanta, GA 30332, USA.
authors.forename: David L
authors.initials: DL
authors.lastname: Miller
authors.forename: Kevin D
authors.initials: KD
authors.lastname: Kubista
authors.forename: Gregory M
authors.initials: GM
authors.lastname: Rutter
authors.forename: Ming
authors.initials: M
authors.lastname: Ruan
authors.forename: Walt A
authors.initials: WA
authors.lastname: de Heer
authors.forename: Phillip N
authors.initials: PN
authors.lastname: First
authors.forename: Joseph A
authors.initials: JA
authors.lastname: Stroscio