8,170 research outputs found
Attractions between charged colloids at water interfaces
The effective potential between charged colloids trapped at water interfaces
is analyzed. It consists of a repulsive electrostatic and an attractive
capillary part which asymptotically both show dipole--like behavior. For
sufficiently large colloid charges, the capillary attraction dominates at large
separations.
The total effective potential exhibits a minimum at intermediate separations
if the Debye screening length of water and the colloid radius are of comparable
size.Comment: 8 pages, 1 figure, revised version (one paragraph added) accepted in
JPC
Typical length scales in conducting disorderless networks
We take advantage of a recently established equivalence, between the
intermittent dynamics of a deterministic nonlinear map and the scattering
matrix properties of a disorderless double Cayley tree lattice of connectivity
, to obtain general electronic transport expressions and expand our
knowledge of the scattering properties at the mobility edge. From this we
provide a physical interpretation of the generalized localization length.Comment: 12 pages, 3 figure
Numerical study of the localization length critical index in a network model of plateau-plateau transitions in the quantum Hall effect
We calculate numerically the localization length critical index within the
Chalker-Coddington (CC) model for plateau-plateau transitions in the quantum
Hall effect. Lyapunov exponents have been calculated with relative errors on
the order . Such high precision was obtained by considering the
distribution of Lyapunov exponents for large ensembles of relatively short
chains and calculating the ensemble average values. We analyze thoroughly
finite size effects and find the localization length critical index .Comment: 4 pages, 4 figure
Enhancing thermoelectric properties of graphene quantum rings
We study the thermoelectric properties of rectangular graphene rings
connected symmetrically or asymmetrically to the leads. A side-gate voltage
applied across the ring allows for the precise control of the electric current
flowing through the system. The transmission coefficient of the rings manifests
Breit-Wigner line-shapes and/or Fano line-shapes, depending on the connection
configuration, the width of nanoribbons forming the ring and the side-gate
voltage. We find that the thermopower and the figure of merit are greatly
enhanced when the chemical potential is tuned close to resonances. Such
enhancement is even more pronounced in the vicinity of Fano like
anti-resonances which can be induced by a side-gate voltage independently of
the geometry. This opens a possibility to use the proposed device as a tunable
thermoelectric generator.Comment: 6 pages, 5 figures, accepted for publication in Physical Review
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