Nonlinear Ionic Excitations, Dynamic Bound States, and Nonlinear Currents in a One‐dimensional Plasma

Abstract

We study the role of nonlinear effects in a classical one-dimensional model of a conducting electron-ion system. In particular we investigate the excitations of strongly nonlinear deformed phonons (cnoidal waves, solitons) on electric currents. We show that in a nonlinear lattice a new type of dynamic bound states of solitons and electrons ("solectrons") may be formed. In our simulations we use Langevin dynamics with N = 10 ions and periodic boundary conditions. The electron-ion interaction is modelled by screened Coulomb forces with appropriate cut-off at small distance; the ion-ion interaction is approximated by an exponential repulsion. Under the influence of a weak external electrical field, the charged particles and "solectrons" yield a stochastic current in the direction of the field. We study several mechanisms to generate and maintain the "solectrons". Then we show how the system develops driven ionic solitons moving opposite to the field. Since the extra current driven by the solitons is (nearly) independent on the external field we find a strongly nonlinear current field characteristics corresponding for small fields to a highly conducting state.

Anharmonic Excitations, Time Correlations and Electric Conductivity

“…Clearly, such excitations like so-called anharmonic phonons or highly deformed phonons are nothing more than solitons in the currently used nonlinear nomenclature [9,11,34,35]. The above comments justify to some extent the interest of our earlier work [1,2,4,5,8] where we have shown that the dynamics of ion rings with Toda or Morse interactions leads to soliton-like excitations and the already mentioned electron-soliton dynamic bound states (for simplicity denoted by solectrons). The rather deep potential well ( Fig.…”

“…One advantage of this method is that the formulation is independent of the dimension of the sample. From such a perspective we have a theory valid also in two-dimensional or quasi-twodimensional materials in a heat bath without assuming external driving of the excitations, thus overcoming one of the mentioned shortcomings of earlier work [1][2][3][4][5][6]8]. Before embarking in such an approach it is worth recalling a few features about electric transport in electron-ion systems.…”

“…Further details about the dynamics and statistical mechanics of the lattice system and the proposed transport process have been provided in several other publications [2][3][4][5][6][7][8]. Besides the general theory [1,4,5,7] we developed the theory in two different lines: (i) applications to the conductivity of gaseous and solid state plasmas [2], (ii) applications to biomolecules [3,6].…”

Hopping Transport and Stochastic Dynamics of Electrons in Plasma Layers

“…In preceding works [1][2][3][4][5][6][7][8] a soliton-mediated new form of non-Ohmic fast electric conduction has been proposed and studied in detail albeit mostly for one-dimensional (1d-) systems. In recent work we extended these studies to two-dimensional systems of electrons and atoms using adiabatic semi-classical approximations [4,5,[7][8][9][10][11].…”

“…In difference to earlier work [2,6] we use here the tight-binding approximation [24][25][26] as more appropriate to the kind of problems treated here [26].…”