Prosenjit Singha Deo

I work on various aspects of mesoscopic systems, like electron transport based on Landauer Buttiker approach, persistent currents in open and closed systems, many body effects in Quantum dots and rings, thermodynamic properties of mesoscopic superconductors etc.

Mesoscopic physics is a part of condensed matter physics, and is mainly concerned with studying the properties of materials that are so small that at low temperatures, the quantum mechanical wavefunction coherently extends over the whole sample and boundary conditions start playing a very significant role. The sample dimensions start competing with the internal length scales like elastic mean free path, inelastic mean free path, etc.

There are several counterintuitive mesoscopic phenomenon such as persistent currents, quantization of conductance, universal conductance fluctuations,...

A mesoscopic sample can be open or closed. An open sample is connected to one or more electron reservoirs through ideal leads. The sample can exchange particles with the reservoirs through the leads. Hence it is basically a grand canonical system, that is however slightly different from that what we study in text books on statistical mechanics, in the sense, that the leads and the reservoirs change the properties of the sample to some extent. While we have studied in text books that a grand canonical system has the same eigenenergies as that when the system is closed, and the reservoir is characterized by a chemical potential. But in a mesoscopic sample we have to account for the fact that the eigenenergies can be changed by the reservoir and the leads that offer a mechanisms for particle exchange between the system and the reservoir. The Landauer-Buttiker approach is to understand such a sample in terms of the scattering matrix, rather than the partition function or free energy.

Back to Condensed Matter Homepage

Email: deo@bose.res.in