Danish Ph.D. School in Nonlinear Science

Sponsored by the Danish Research Agency


Under this aspect of the program, it is proposed that new types of cryogenic electronic components will be designed and fabricated, which are based on superconducting materials and on combinations of superconductors and heterostructures of semiconductors and semimetals. Experimental and theroretical investigations are bring carried out on nonlinear superconductors, on mesoscopic, superconductor-semiconductor components and devices and on single electron tunneling effects. These new electronic components share one feature: they are very fast and sensitive because they involve temporal or spatial coherence which stem from quantum and/or mesoscopic effects in minute volumes (micro- or nano-scale electronics).
In long Josephson junctions magnetic flux quanta are modelled as sine-Gordon solitons (`fluxons') and their dynamic behaviour is calculated both analytically and numerically and compared with experimental measurements. These effects are enhanced by the use of arrays of coupled junctions. In superconducting transistors the much reduced ohmic losses imply improvements of the device transit frequency.
In practice, the research efforts are focussed on the following types of electronic components and devices: Single Electron Transistors (SETs), Superconducting Field Effect Transistors (SUPRAFETs), Rapid Single Flux Quantum electronics (RSFQ), Superconducting Quantum Interference Devices (SQUIDs) and Josephson oscillators. The research is carried out in collaboration with NKT Research Center A/S.