Co-organization of scientific meeting; The scope of the meeting is to focus on new approaches to theory of ultrafast phenomena in correlated electronic systems as well as related experimental observation. This covers fundamental problems of hot carrier relaxation in strange metals, collective phenomena and quasi-particle relaxation in superconductors, charge and spin density way systems, excitonic and Mott insulators and related materials.
B.01 Organiser of a scientific meeting
COBISS.SI-ID: 29106983A pseudogap (PG) was introduced by Mott to describe a state of matter which has a minimum in the density of states at the Fermi level, deep enough for states to become localized. It can arise either from Coulomb repulsion between electrons, or due to an incipient charge or spin order, or a combination of the two. These states are rapidly fluctuating in time with random phase, so they are hard to observe experimentally. Here we present the first coherent quench measurements of the dynamical transition to the pseudogap state in the prototype high temperature superconductor Bi2Sr2CaCu2O8+δ, revealing a marked absence of incipient collective ordering beyond a few coherence lengths on short timescales at any level of doping. Instead we find evidence for sub-picosecond carrier localization favouring a picture of pairing resulting from the competing Coulomb interaction and strain, enhanced by a Fermi surface instability.
B.04 Guest lecture
COBISS.SI-ID: 28974631In complex materials where competing orders are present, non-equilibrium experiments can reveal the hierarchy of interactions that eventually determine the dominant order. The pursuit of such non-equilibrium phenomena also reveals new states of matter, which cannot be reached under equilibrium conditions. In complex systems, such as cuprate superconductors and the currently fashionable layered chalcogenide systems, particularly strain and Coulomb interactions conspire to give different kinds of broken symmetry states. Here we compare the metastable polaronic states in TaS2 with cuprate superconductors, to find remarkable similarities in stripe formation and metastability phenomena associated with glassy relaxation dynamics. Considering how superficially different these materials are, the similarity in their respective phenomenologies reveals an unexpected universality of the underlying mechanism for the formation of broken symmetry states in these materials.
B.04 Guest lecture
COBISS.SI-ID: 28725799