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Contenuto archiviato il 2022-12-23

Non-Linear Phenomena in 2D charged systems on liquid helium

Obiettivo

Low-dimensional electron systems are of great interest for fundamental physics and applications. This project is collaboration between teams in Kharkov, Chernogolovka, Tbilisi, Jerusalem, Konstanz, Grenoable and London to investigate, experimentally and theoretically, the non-linear properties of strongly correlated electrons on cryogenic substrates. New technologies are also being developed for these experiments: grooved structures on insulating substrates; metallic strips and etched structures and multi-layer microfabrication to provide one and zero-dimensional structures.
The Network will hold regular research and discussion meetings, publish a Newsletter and foster collaborative research and scientific exchanges between teams in Russia, Ukraine, Georgia and INTAS countries, particularly Germany, France, Israel and England. The duration of this Network will be 36 months.

Low-dimensional electron systems are of great interest for fundamental physics. Two-dimensional (2D) electrons on cryogenic substrates such as liquid helium are an ideal system for investigating fundamental phenomena. These 2D electrons are strongly interacting, both with each other and with the helium substrate. This leads to many interesting correlation and non-linear effects, which play a significant role in the behaviour of the charged liquid helium surface. The scientific objectives of this Network are to investigate, experimentally and theoretically, some important non-linear properties of 2D electrons on liquid helium.
At low temperatures the 2D electrons form a unique Wigner crystal. It is now clear that the motion and conduction of a 2D crystal is intrinsically non-linear due to strong coupling between the electron solid and the liquid surface. The influence of such a coupling on the features of the non-linear Wigner solid I-V characteristics, the yield strength, shear modulus and the nature of its plastic flow in the presence of a magnetic field and the properties of the so-called sliding Wigner crystal will be studied.
The non-linear "polaron" problem is also very interesting. In strong vertical pressing electric fields, for electrons on helium films and in the solid phase, polarons are formed as the electron produces a deformation of the helium surface. The behavior of charged solitons (the analog of the same surface phenomenon in neutral liquids), the electron-vortex coupling in thin helium films near the Kosterlitz-Thouless transition in the superfluid film and the special features of the electron dimples in quasi one-dimensional channels and in other restricted geometries will be investigated. Related vortex dynamics will also be investigated.
Another interesting non-linear phenomenon to be investigated is that of energetic time-relaxation for the 2D electron system above liquid helium and its dependence on a variety of different external parameters such as temperature, pressing electric field and especially magnetic field. The studies described above involve both theoretical and experimental efforts.
A second, related, theme of the Network is to study electrons in reduced dimensional structures, using techniques developed by members of the teams, to study the pinning of the Wigner crystal; localisation in 1-dimensional (1D) and quasi-1D channels; artificial atoms in 0D and Q0D classical dots.

Scientific results from the Network are expected in the following fields:
(i) Non-linear effects in two-dimensional electron crystals;
(ii) Measurement of the plasticity, strength and shear modulus of Wigner crystals;
(iii) Solitons on a Charged Liquid Surface;
(iv) Vortex-polaron and other interactions;
(v) Quasi-one-dimensional and one-dimensional electron systems on liquid helium.

Invito a presentare proposte

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Meccanismo di finanziamento

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Coordinatore

Royal Holloway University of London
Contributo UE
Nessun dato
Indirizzo
Egham hill
TW20 0EX Egham
Regno Unito

Mostra sulla mappa

Costo totale
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Partecipanti (6)