4 research outputs found
Electron transport in a quasi-one dimensional channel on suspended helium films
Quasi-one dimensional electron systems have been created using a suspended
helium film on a structured substrate. The electron mobility along the channel
is calculated by taking into account the essential scattering processes of
electrons by helium atoms in the vapor phase, ripplons, and surface defects of
the film substrate. It is shown that the last scattering mechanism may dominate
the electron mobility in the low temperature limit changing drastically the
temperature dependence of the mobility in comparison with that controlled by
the electron-ripplon scattering.Comment: 4 pages, 1 figur
Intersubband plasmons in quasi-one-dimensional electron systems on a liquid helium surface
The collective excitation spectra are studied for a multisubband
quasi-one-dimensional electron gas on the surface of liquid helium. Different
intersubband plasmon modes are identified by calculating the spectral weight
function of the electron gas within a 12 subband model. Strong intersubband
coupling and depolarization shifts are found. When the plasmon energy is close
to the energy differences between two subbands, Landau damping in this finite
temperature system leads to plasmon gaps at small wavevectors.Comment: To be published as a Rapid Communication in Phys. Rev.
Generic properties of a quasi-one dimensional classical Wigner crystal
We studied the structural, dynamical properties and melting of a
quasi-one-dimensional system of charged particles, interacting through a
screened Coulomb potential. The ground state energy was calculated and,
depending on the density and the screening length, the system crystallizes in a
number of chains. As a function of the density (or the confining potential),
the ground state configurations and the structural transitions between them
were analyzed both by analytical and Monte Carlo calculations. The system
exhibits a rich phase diagram at zero temperature with continuous and
discontinuous structural transitions. We calculated the normal modes of the
Wigner crystal and the magneto-phonons when an external constant magnetic field
is applied. At finite temperature the melting of the system was studied via
Monte Carlo simulations using the (MLC). The
melting temperature as a function of the density was obtained for different
screening parameters. Reentrant melting as a function of the density was found
as well as evidence of directional dependent melting. The single chain regime
exhibits anomalous melting temperatures according to the MLC and as a check we
study the pair correlation function at different densities and different
temperatures, formulating a different criterion. Possible connection with
recent theoretical and experimental results are discussed and experiments are
proposed.Comment: 13 pages text, 21 picture
ON MOBILITY OF SURFACE ELECTRONS IN LIQUID HELIUM AT TEMPERATURES UP TO 20 mK
On a mesuré la mobilité électronique sur la surface de l'hélium liquide à des températures de 20 mK à 1 K. On a déterminé la mobilité des électrons superficiels au moyen de l'absorption d'énergie du champ électromagnétique. Les auteurs ont constaté que dans cette gamme de température la dépendance de la mobilité électronique en fonction de la température est voisine de T-l.The mobility of electrons across the liquid helium surface has been measured in the temperature range of 20 mK-1 K. The mobility of surface electrons is estimated by the electromagnetic energy absorption. It has been found that in the temperature range studied, the temperature dependence of the electron mobility is close to T-1