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Contenido archivado el 2022-12-23

Thermo-magnetic transport in surface superlattices

Objetivo

Nanostructured two-dimensional (2D) systems continue to be the subject of intense study, both in terms of their fundamental physical properties as well as applications that may arise. Many recent works were devoted to the study of electron transport in both electrostatically and magnetically modulated surface superlattices (SSL). The most pronounced features of electron transport in SSL are so-called commensurability magnetoresistance oscillations, which can be described in the framework of dynamic chaos theory. Quantum interference phenomena observed in SSL composed of antidot arrays also reflect the dynamically chaotic nature of electron transport. The experimental data obtained so far are, however, fragmentary and thus insufficient for the development of a universal picture of these phenomena in SSL. Quantum effects in SSL with magnetic modulation have not been investigated at all. It should be also noted that to date the study of SSL has been largely restricted to the investigation of magnetoresistance while another kinetic coefficient - the thermopower - remains practically uninvestigated.

The present project is aimed at an experimental and theoretical study of the thermo-magnetic transport properties of SSL with electrostatic and magnetic modulation, thus filling the gap in the current understanding of the kinetic properties of SSL. Both quasiclassical effects connected with geometrical resonances, and quantum interference phenomena will be investigated, relationship between them will be clarified, and comparison with usually studied magneto-transport properties will be made. The advantages of thermo-power measurements will be used to investigate electron-electron interactions in electrostatic and magnetic SSL. The study of thermo-magnetic effects in SSL will be completed by experimental observation and investigation of the new theoretically predicted EMF originating from the asymmetry of electron-phonon interactions in 2DEG with asymmetric quantizing potential in the presence of a magnetic field.

The study of the thermo-magnetic properties of SSL should yield the following results:

Experimental observation of commensurability oscillations in thermo-power. Clarification of the role of specific stable electron trajectories responsible for the features of magnetic field dependence of thermo-power and magnetoresistance.
Experimental observation of mesoscopic thermopower fluctuations, determination of the spectrum of these fluctuations and the temperature dependence of amplitude. Finding the correlation between mesoscopic thermopower and conductance fluctuations. Verification of the universality of mesoscopic thermopower fluctuations.
Observation of a T5 law due to e-e Umklapp processes in SSLs. Observation of additional small angle e-e scattering in the thermopower only. Identification of possible differences between electrostatic and magnetic SSLs; notably the consequences of electron density modulation.
Experimental observation of new EMF originating from asymmetry of electron-phonon interactions in the presence of magnetic field parallel to the 2DEG plane. Clarification of the influence of superlattice potential on the behaviour of this EMF in SSL.

The proposed programme will make a vital contribution to the development of a complete physical picture of transport phenomena in surface superlattices.

Convocatoria de propuestas

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Régimen de financiación

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Coordinador

UNIVERSITY OF BATH
Aportación de la UE
Sin datos
Dirección
CLAVERTON DOWN
BATH
Reino Unido

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Coste total
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Participantes (3)