Transport Measurements Across a Tunable Potential Barrier in Graphene

Abstract

The peculiar nature of electron scattering in graphene is among many exciting theoretical predictions for the physical properties of this material. To investigate electron scattering properties in a graphene plane, we have created a gate-tunable potential barrier within a single-layer graphene sheet. We report measurements of electrical transport across this structure as the tunable barrier potential is swept through a range of heights. When the barrier is sufficiently strong to form a bipolar junction (n-p-n or p-n-p) within the graphene sheet, the resistance across the barrier sharply increases. We compare these results to predictions for both diffusive and ballistic transport, as the barrier rises on a length scale comparable to the mean free path. Finally, we show how a magnetic field modifies transport across the barrier.

Tuning the Electronic Structure of Graphene by an Organic Molecule

“…[2][3][4][5][6] As a 2D crystal, graphene was found to exhibit high crystal quality, 1,7,8 in which charge carriers can travel thousands of interatomic distances without being scattered. [9][10][11] In particular, due to its special honeycomb structure, the band structure of graphene exhibits two intersecting bands at two inequivalent K points in the reciprocal space, and its low energy excitations are massless Dirac Fermions near these K points because of the linear (photon-like) energymomentum dispersion relationship.…”

Landau level spectra and the quantum Hall effect of multilayer graphene

“…Since the isolation of graphene flakes, 1 the chiral nature of quasiparticles in monolayer and bilayer graphene has been observed in a range of phenomena including the integer quantum Hall effect, [2][3][4] Klein tunneling, [5][6][7][8] weak localization, [9][10][11][12][13][14][15][16] and photoemission. [17][18][19][20] Generally speaking, the effective mass models [21][22][23][24][25][26][27][28][29][30] of monolayer and bilayer graphene have been very successful in describing these phenomena.…”

Effect of a gap opening on the conductance of graphene superlattices

“…Graphene superlattices, on the other hand, may be fabricated by adsorbing adatoms on graphene surface by positioning and aligning impurities with scanning tunneling microscopy [41], or by applying a local top gate voltage to graphene [42]. The transition of hitting massless particles in a clean [43] or disordered [44] graphene-based superlattice structure has been studied.…”