Dr. Robert A. Kaindl, Materials Sciences Division, Lawrence Berkeley National Lab

"Ultrafast Views of Quantum Materials: from Quasiparticles to Emergent Order"

Coffee and cookies will be served at 3:45pm in RLM 4.102

Abstract: The doping of charges in Mott insulators gives rise to a wealth of emergent phenomena including high-TC superconductivity, colossal magnetoresistance, and charge-ordered phases. However, conventional adiabatic tuning of phase transitions can mask the causal time ordering of rapid fundamental interactions, motivating the use of time-resolved probes. I will discuss experiments that employ femtosecond light pulses in the terahertz, mid-IR and X-ray regime to study fast cooperative dynamics in correlated solids. Besides ultrafast interactions underlying the pairing of electronic quasiparticles in superconductors, I will focus on experiments that reveal how atomic-scale charge, spin, and vibrational patterns called “stripes” melt and form. In nickelates as a model system, the transient terahertz-frequency conductivity provides new insight into the time evolution and mutual coupling of the charges and symmetry-broken crystal lattice. Access to such physics of correlated materials on ultrashort time scales promises new ways for disentangling their complex phase diagrams and creating non-thermal phases far from equilibrium.