We report on photoinduced phase transition to a hidden state in a layered material 1T-TaS2. Unlike any other reported photoinduced states, the one observed here is completely stable at low temperatures.
B.06 Other
COBISS.SI-ID: 27404583A significant effort was invested into investigation of dynamical phase transitions in superconducting and CDW systems. The control of condensed matter systems out of equilibrium by laser pulses allows us to investigate the system trajectories through symmetry-breaking phase transitions. Thus the evolution of both collective modes and single-particle excitations can be followed through diverse phase transitions with femtosecond resolution. We presented experimental observations of the order parameter trajectory in the normal → superconductor transition and charge density wave ordering transitions. Of particular interest is the coherent evolution of topological defects forming during the transition via the Kibble–Zurek mechanism, which appears to be measurable in optical pump–probe experiments. Experiments on CDW systems reveal some new phenomena, such as coherent oscillations of the order parameter, the creation and emission of dispersive amplitude modes upon the annihilation of topological defects, and mixing with weakly coupled finite frequency (massive) bosons as described in J. Phys.: Condens. Matter 25, 404206 (2013). The paper was written at the invitation of Tom Kibble, and the entire journal issue was devoted to Cosmology in the laboratory experiments in his honour. The paper also reveals some new ideas concerning dark matter excitations within the phase transition picture in and discusses the observation of the annihilation of domain walls and the ensuing emission of Higgs bosons detected in femtosecond optical experiments.
B.04 Guest lecture
COBISS.SI-ID: 27260199