48,024 research outputs found
Inhomogenous electronic structure, transport gap, and percolation threshold in disordered bilayer graphene
The inhomogenous real-space electronic structure of gapless and gapped
disordered bilayer graphene is calculated in the presence of quenched charge
impurities. For gapped bilayer graphene we find that for current experimental
conditions the amplitude of the fluctuations of the screened disorder potential
is of the order of (or often larger than) the intrinsic gap induced by
the application of a perpendicular electric field. We calculate the crossover
chemical potential, , separating the insulating regime from a
percolative regime in which less than half of the area of the bilayer graphene
sample is insulating. We find that most of the current experiments are in the
percolative regime with . The huge suppression of
compared with provides a possible explanation for
the large difference between the theoretical band gap and the
experimentally extracted transport gap.Comment: 5 Pages, 2 figures. Published versio
Theory of carrier transport in bilayer graphene
We develop a theory for density, disorder, and temperature dependent
electrical conductivity of bilayer graphene in the presence of long-range
charged impurity scattering as well as an additional short-range disorder of
independent origin, establishing that both scattering mechanisms contribute
significantly to determining bilayer transport properties. We find that
although strong screening properties of bilayer graphene lead to qualitative
differences with the corresponding single layer situation, both systems exhibit
the linearly density dependent conductivity at high density and the minimum
graphene conductivity behavior around the charge neutrality point due to the
formation of inhomogeneous electron-hole puddles induced by the random charged
impurity centers.Comment: 5 pages, 4 figure
Soft gluon multiplicity distribution revisited
In this paper the soft gluon radiation from partonic interaction of the type:
+ gluon has been revisited and a correction term to the widely used
Gunion-Bertsch (GB) formula is obtained.Comment: Few typos corrected, to appear in Phys. Rev. D (rapid communication
Graphene magnetoresistance in a parallel magnetic field: Spin polarization effect
We develop a theory for graphene magnetotransport in the presence of carrier
spin polarization as induced, for example, by the application of an in-plane
magnetic field () parallel to the 2D graphene layer. We predict a negative
magnetoresistance for intrinsic graphene, but for
extrinsic graphene we find a non-monotonic magnetoresistance which is positive
at lower magnetic fields (below the full spin-polarization) and negative at
very high fields (above the full spin-polarization). The conductivity of the
minority spin band electrons does not vanish as the minority carrier
density () goes to zero. The residual conductivity of electrons at
is unique to graphene. We discuss experimental implications of our
theory.Comment: 5 pages, 3 figure
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