Field theoretic description of the abelian and non-abelian Josephson effect: The role of pseudo-Goldstone Bosons
We formulate the Josephson effect in a field theoretic language whichaffords a straightforward generalization to the non-abelian case. Ourformalism interprets Josephson tunneling as the excitation of pseudo-Goldstone bosons. We demonstrate the formalism through theconsideration of a single junction separating two regions with apurely non-abelian order parameter and a sandwich of three regionswhere the central region is in a distinct phase. Applications tovarious non-abelian symmetry breaking systems in particle andcondensed matter physics are given.
09/01/2009 at 4:00 pm
Prof. Paolo Milani, Interdisciplinary Centre for Nanostructured Materials and Interfaces(CIMAINA)
Special Colloquium
Lecture Hall
Document Date:
Supersonic cluster beam deposition : a tool for nanoscale science and technology
Supersonic cluster beam deposition : a tool for nanoscale science and technology
Gas phase nanoparticle production, manipulation and deposition is of primary importance for the synthesis of novel nanostructured systems and for the development of industrial processes based on the convergence of micro- and nanofabrication. I will present and discuss an approach, based on supersonic cluster beam, introducing cluster sources, nanoparticle particle formation and growth mechanisms and the use of aerodynamic focusing methods that are coupled with supersonic expansions to obtain high intensity cluster beams with a control on nanoparticle mass and spatial distribution. The relevance of this approach for fundamental research and applications will be highlighted
07/01/2008 at 4:00 pm
Dr. J.K. Tripathi, Institute of Physics
Seminar of General Interest
Lecture Hall
Document Date:
Tuning magnetic property of Pt/Cr/Co multilayer by Ion Irradiation
Tuning magnetic property of Pt/Cr/Co multilayer by Ion Irradiation
In recent years, it has been shown that magnetic properties ofultrathin magnetic multilayers depend strongly on the surface andinterface structure, chemical composition, crystallinity, and grain sizesand their distributions. In general, all these structural properties canbe tuned by ion irradiation. In addition, it has been shown that themagnetic properties can also be tuned by ion irradiation. In this seminar,I shall talk on tuning the magnetic properties of ultrathin magneticmultilayers by ion irradiation
08/01/2008 at 4:00 pm
Seminar of General Interest
Lecture Hall
Document Date:
Swift heavy ion irradiation induced modifications in CdTe and CdS thin films
Swift heavy ion irradiation induced modifications in CdTe and CdS thin films
The effect of Swift Heavy Ion (SHI) irradiation on semiconductor materialsand devices is of significance both from fundamental as well asapplication aspects. Interesting phenomena like phase transformation incrystalline solids, sputtering of target material, surface and interfacemorphological changes, modification of optical band gap, etc have beenreported on thin films of metals/semiconductors. The II-VI compoundsemiconductors such as CdTe and CdS are widely studied for their provenapplications in optoelectronic devices such as solar cells, detectors,light emitting diodes, etc. Since the properties have strong dependence onthe preparation conditions and post deposition treatments, interest on themodification of thin film properties with the aid of novel techniques hasincreased. In this constitution, the successful exploitation of SHIirradiation to induce modifications in the properties of CdTe and CdS thinfilms has been studied. The evaporated films of CdTe and CdS wereirradiated with 100 MeV silver and 80 MeV oxygen ions and the propertieswere studied by X-ray diffraction, scanning electron microscopy (SEM),atomic force microscopy (AFM), optical absorption/transmittance,photoluminescence, and X-ray photoelectron spectroscopy. Upon irradiation,most of the important properties such as grain size, stress, optical bandgap, electronic structure, and native defects show significant changes
30/12/2007 at 4:00 pm
Prof. X.Vinas, Department of Physics, University of Barcelona, Spain