Self-Diffusion in a Spatially Modulated System of Electrons on Helium

We present results of molecular dynamics simulations of the electron system on the surface of liquid helium. The simulations are done for 1600 electrons with periodic boundary conditions. Electron scattering by capillary waves and phonons in helium is explicitly taken into account. We find that the...

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Bibliographic Details
Published in:Journal of low temperature physics 2019-05, Vol.195 (3-4), p.266-288
Main Authors: Moskovtsev, K., Dykman, M. I.
Format: Article
Language:English
Subjects:
Boundary conditions
Capillary waves
Characterization and Evaluation of Materials
Condensed Matter Physics
Coupling (molecular)
Diffusion coefficient
Free electrons
Freezing
Liquid helium
Low temperature physics
Magnetic Materials
Magnetism
Molecular dynamics
Physics
Physics and Astronomy
Self diffusion
Solid phases
Solitary waves
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Summary:We present results of molecular dynamics simulations of the electron system on the surface of liquid helium. The simulations are done for 1600 electrons with periodic boundary conditions. Electron scattering by capillary waves and phonons in helium is explicitly taken into account. We find that the self-diffusion coefficient superlinearly decreases with decreasing temperature. In the free-electron system, it turns to zero essentially discontinuously, which we associate with the liquid-to-solid transition. In contrast, when the system is placed in the fully commensurate one-dimensional potential, the freezing of the diffusion occurs smoothly. We relate this change to the fact that, as we show, a Wigner crystal in such a potential is stable, in contrast to systems with a short-range inter-particle coupling. We find that the freezing temperature nonmonotonically depends on the commensurability parameter. We also find incommensurability solitons in the solid phase. The results reveal peculiar features of the dynamics of a strongly correlated system with long-range coupling placed into a periodic potential.
ISSN:0022-2291
1573-7357
DOI:10.1007/s10909-019-02148-z