Nonlinear excitations and electric
transport in dissipative Morse-Toda lattices |
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Authors: | A P Chetverikov W Ebeling M G Velarde |
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Institution: | 1. Instituto Pluridisciplinar, Universidad Complutense, Paseo Juan XXIII, 1, 28040, Madrid, Spain 2. Faculty of Physics, Saratov State University, Astrakhanskaya 83, 410012, Saratov, Russia 3. Institut für Physik, Humboldt-Universit?t Berlin, Newtonstr. 15, 12489, Berlin, Germany
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Abstract: | We investigate the onset and maintenance of nonlinear soliton-like excitations in chains
of atoms with Morse interactions at rather high densities, where
the exponential repulsion dominates.
First we discuss the atomic interactions and approximate the
Morse potential by an effective Toda potential with
adapted density-dependent parameters.
Then we study several mechanisms to generate
and stabilize the soliton-like excitations:
(i) External forcing: we shake the masses periodically, mimicking a
piezoelectric-like excitation, and delay subsequent damping
by thermal excitation;
(ii) heating, quenching and active friction:
we heat up the system to a relatively high temperature Gaussian
distribution, then quench to a low temperature,
and subsequently stabilize by active friction. Finally,
we assume that the atoms in the chain are ionized with free electrons able to move along the lattice.
We show that the nonlinear soliton-like excitations
running on the chain interact with the electrons. They
influence their motion in the presence of an external field creating dynamic
bound states (“solectrons”, etc.). We show that these
bound states
can move very fast and create extra current.
The soliton-induced contribution to the current
is constant, field-independent for a significant range of values when approaching the zero-field value. |
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Keywords: | 05 70 Fh Phase transitions: general studies 05 40 Jc Brownian motion 05 70 Ln Nonequilibrium and irreversible thermodynamics |
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