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arXiv · 1006.2058

Yukawa particles confined in a channel and subject to a periodic potential: ground state and normal modes

J. C. N. Carvalho·W. P. Ferreira·G. A. Farias·F. M. Peeters
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Abstract

We consider a classical system of two-dimensional (2D) charged particles, which interact through a repulsive Yukawa potential $exp(-r/λ)/r$, confined in a parabolic channel which limits the motion of the particles in the $y$-direction. Along the $x$-direction, the particles are also subject to a periodic potential substrate. The ground state configurations and the normal mode spectra of the system are obtained as function of the periodicity and strength of the periodic potential ($V_0$), and density. An interesting set of tunable ground state configurations are found, with first and second order structural transitions between them. A magic configuration with particles aligned in each minimum of the periodic potential is obtained for V_0 larger than some critical value which has a power law dependence on the density. The phonon spectrum of different configurations were also calculated. A localization of the modes into a small frequency interval is observed for a sufficient strength of the periodic potential. A tunable band-gap is found as a function of $V_0$. This model system can be viewed as a generalization of the Frenkel and Kontorova model.

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J. C. N. Carvalho, W. P. Ferreira, G. A. Farias, F. M. Peeters. 2010-06-10. Yukawa particles confined in a channel and subject to a periodic potential: ground state and normal modes. https://doi.org/10.1103/physrevb.83.094109

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