Following the recent surge in interest in ultrafast studies of superconductors and related materials, and particularly a flurry of activity in quantum mechanical theory of non-equilibrium phenomena we organised a short and focused ad-hoc 3-day meeting. The scope of the meeting was to focus on new approaches to theory of ultrafast phenomena in cuprates and related systems, including fundamental problems of hot carrier relaxation in strange metals, collective phenomena and single particle relaxation. We were able to bring together two national and three foreign groups from Germany and Italy.
B.01 Organiser of a scientific meeting
COBISS.SI-ID: 26372647Ultrashort laser pulses are a convenient tool for coherent excitation of phonons and collective electronic-lattice modes in CDW systems. Due to the availability of strong laser pulses the phonons can be driven far from equilibrium, exposing nonlinear effects. These effects are often difficult to track by the standard pump-probe optical spectroscopy due to the presence of large first-order signals. Trying to overcome this problem we devised a differential multi-pump-pulse technique that enables us to detect small differences between highly excited trajectories of a system. Using this technique we were able to investigate a hitherto unexplored aspect of the CDW amplitude mode behavior under strongly driven nonequilibrium conditions. By means of this approach we are able to directly investigate the anharmonicity of the effective AM potential, as well as detect the anharmonic coupling of the collective bosonic mode (the AM) of the CDW to other lattice modes in 1T-TaS2 and TbTe3. Apart from the coherent response we use the same technique to study the incoherent recombination of topological defects after a quench of the system by an intense laser pulse. The evolution of the AM is found to follow a slower recovery due to incoherent annihilation of the topological defects on a timescale up to ~30 ps and is fairly consistent with the thermal diffusion on longer timescales.
B.04 Guest lecture
COBISS.SI-ID: 26132263The existence of hidden ground states which exist in parallel worlds of symmetry breaking transitions can be brought into view if a system takes trajectory to a state of matter which is unreachable under thermodynamic conditions.We report on the switching to a new kind of hidden state in 1T-TaS2 formed by many-body interactions under non-equilibrium conditions created by a single 50fs laser pulse.
B.04 Guest lecture
COBISS.SI-ID: 25946663Group Members have coorganized 12th international scientific konference SLONANO 2012 which hosted some exceptional foreign and national speakers, young researchers and members of industry.
B.01 Organiser of a scientific meeting
COBISS.SI-ID: 3340145Konstanz University, Germany awarded Viktor Kabanov with The Senior Fellowship for his exceptional academic achievements in the field of superconductivity and higtemperature superconductivity.
B.05 Guest lecturer at an institute/university