Novel Phenomena in Small Structures


SMALL STRUCTURES - 8050

Work Area: Physics of Mesoscopic Quantum Structures

Keywords quantum electronics, mesoscopics superconductivity, quantum Hall effect


Start Date: to be announced / Status: starting

[ participants / contact ]


Abstract The SMALL STRUCTURES working group will study the theoretical foundations of mesoscopic (ms) solid state systems in the size range from a few nm to about a nm at low T, including metallic and semiconducting systems. Main topics are: ms electronic systems, ms superconductivity and Josephson junction arrays, Quantum Hall effect; the aim is to elucidate the quantum nature of electronic excitations and transport phenomena at the ms scale, and assess implications of these basic theoretical aspects on applications to quantum ms electronic devices.


Aims

Recent technological innovations have made the fabrication of high quality semiconductor heterostructures (quantum Hall devices) possible, as well as Josephson junction arrays with flexible geometrical patterns and very small structures out of metals and semiconductors (wires, rings, quantum dots). This working group will study the theoretical foundations of mesoscopic solid state systems in the size range from a few nm to about a nm at low temperatures, including metallic and semiconducting systems, in order to clarify the ultimate restrictions posed by quantum phenomena on the design and performance of miniaturised electronic devices made by these novel structures. Emphasis will be on: 1) Mesoscopic electronic systems, 2) Mesoscopic superconductivity and Josephson junction arrays, 3) Quantum Hall effect.

The aim of the group is to elucidate the quantum nature of electronic excitations and transport phenomena at the mesoscopic scale, where phase coherence is not destroyed by inelastic scattering processes but superconducting coherence may hold. In all three topics magnetic field effects play a very important role, leading to frustration in Josephson junction arrays and to a wealth of new phenomena in quantum Hall systems (eg even denominator fractional FGHE, or Wigner crystallisation).

Activities

Over a hundred scientists are expected to meet at the ISI in Torino for extended periods to work on specific theoretical problems and to discuss relevant experimental results. The approach chosen in this working group will be very similar to that of the successful ESPRIT B.R.A. Ní 3014, High-Temperature Superconductivity: Concepts, Models and Methods. During each year, theoretical research will be carried out in each of the topics, with a changing focus from year to year. The duration of the activities will be about 9 weeks per year, with a distribution among the different topics depending on the actual most relevant problems. An average of 10 scientists will work together at the ISI at any given time of the activities. The research will be supplemented by daily seminars and a yearly open international conference.

Potential

In the short term, the research carried out by the working group should lead to a better understanding of the physics at the basis of the new miniaturised electronic devices based on mesoscopic (micron and submicron size scale) structures as well as of the prespectives of going beyond the present limits of industrial miniaturisation. In the medium term, it should allow assessment of feasibility and possible functions of novel devices, clarifying operation limits and possible new development strategies raising from new effects.


Coordinator

FONDAZIONE I.S.I. - I
Istituto Interscambio Scientifico
Viale Settimio Severo 65
I- 10133 TORINO

Participants

Université de Neuchatel - CH
Paul Scherrer Institute - CH - Universitaet Augsburg - D
Scuola Normale Superiore - I
University of Birmingham - UK

CONTACT POINT

Prof. M. Rasetti
tel +39/11 6603090
fax +39/11 6600049
e-mail: ISI@isi36a.isi.it


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SMALL STRUCTURES - 8050, August 1994


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html version of synopsis by Nick Cook