Université de Genève
Ecole de physique - Département de physique nucléaire et corspusculaire
24, quai Ernest-Ansermet - 1211 GENÈVE 4
Tél: (022) 379 62 73 - Fax: (022) 379 69 92
Lundi 1er décembre 2008
PARTICLE PHYSICS SEMINAR
at 17.00 hrs – Stückelberg Auditorium
Superconducting Interfaces between Insulating Oxide
Prof. Jean-Marc TRISCONE / Université de Genève
At interfaces between complex oxides, electronic systems with unusual properties can be generated. A striking example is the interface between LaAlO3 and SrTiO3, two good insulating perovskite oxides, which was found in 2004 to be conducting with a high mobility. We recently discovered that the ground state of this system is a superconducting condensate, with a critical temperature of about 200 mK. The characteristics observed for the superconducting transitions are consistent with a two-dimensional superconducting sheet as thin as a few nanometers. Recent field effect experiments revealed the sensitivity of the normal and superconducting states to the carrier density. In particular, the electric field allows the tuning of the critical temperature between 200 mK and 0 K, revealing a complex phase diagram and a superconductor to insulator transition. I will discuss the perspectives opened by this new field of research sometimes called "oxide interface engineering.
Lundi 8 décembre 2008
PARTICLE PHYSICS SEMINAR
at 17.00 hrs – Stückelberg Auditorium
The Galaxy in a new light: High energy gamma ray astronomy with H.E.S.S.
Prof. Werner Hofmann / MPI für Kernphysik, Heidelberg
During its first years of operation, the H.E.S.S. array of imaging atmospheric Cherenkov telescopes has revealed a sky full of sources of very high energy gamma rays and has demonstrated the great power of the Cherenkov technique for exploring non-thermal processes in the Universe. High-energy gamma ray astronomy is now delivering sky maps, sources with resolved morphology, and high-resolution light curves, joining up with mainstream astronomy. The talk will illustrate some of the key results from H.E.S.S., mention some of the open questions, and present ideas for the next-generation CTA observatory.
Information: http://dpnc.unige.ch/seminaire/annonce.html
Organizer : Prof. Markus Büttiker