Title: n=0 Landau level shift of graphene stack on SiC

Hongki Min^1,2, Mark D. Stiles¹ and A.H.MacDonald³

¹Center for Nanoscale Science and Technology, National Institute of Standards and Technology, Gaithersburg, MD 20899-6202

²Maryland NanoCenter, University of Maryland, College Park, MD 20742

³Department of Physics, The University of Texas at Austin, Austin, Texas 78712

Graphene is a two-dimensional honeycomb lattice of carbon atoms and it has attracted considerable attention because of experimental progress toward applications in nanoelectronics, and because of exotic chiral features in its electronic structure. Recently, the quantized energy states under magnetic fields (Landau levels) and their spatial profiles were measured at NIST using the scanning tunneling microscope (STM) which probes the local density of states of a material. The results show interesting properties such as n=0 Landau level shifts, increase of the Fermi velocity and breaking of the particle-hole symmetry. To explain these results, we model the graphene stack on the substrate as a two-dimensional array of layers in which charge is distributed classically by electrostatics with the boundary condition given by experimental parameters such as chemical potential and the tip work function. We also discuss possible velocity overestimation and the particle-hole asymmetry in the STM measurements.

CATEGORY: Physics

Author: Hongki Min

Center for Nanoscale Science and Technology

Electron Physics Group

Building 216, Room A251

Mail stop 6202

Tel: (301) 975-4328

Fax: (301) 926-2746

Email: hongki.min@nist.gov

Are you a Sigma Xi Member?   No

Mentor: Mark D. Stiles

Center for Nanoscale Science and Technology

Electron Physics Group

Building 216, Room A235

Mail stop 6202

Tel: (301) 975-3745

Fax: (301) 926-2746

Email: mark.stiles@nist.gov

Is your mentor a Sigma Xi Member?   No