SIMES Seminar: Giacomo Coslovich

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Date(s) - Aug 26 2020
11:00 AM - 12:00 PM

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Light-enhanced Charge Density Wave Coherence in a High-Temperature Superconductor

The use of ultrashort optical and X-ray pulses offers new opportunities to study fundamental interactions in materials exhibiting unconventional quantum states, such as stripes, charge density waves and high-temperature superconductivity. To understand the microscopic interdependence between these states a probe capable of discerning their interaction on its natural length and time scales is necessary. In this talk, I will present ultrafast resonant soft x-ray scattering results tracking the transient evolution of charge density wave correlations in the high temperature superconductor YBa2Cu3O6+x. Ultrashort infrared pulses produce a non-thermal quench of the superconducting state, while X-ray pulses detect the reaction of charge density waves. We observe a picosecond response, characterized by a large enhancement of spatial coherence of charge density waves, nearly doubling their correlation length, and a smaller increase of their amplitude. This ultrafast snapshot directly reveals the interaction between these quantum states on their natural timescales. It demonstrates that their competition manifests inhomogeneously, as disruption of spatial coherence, indicating the role of superconductivity in stabilizing topological defects within charge density waves domains.

Bio:
Giacomo Coslovich has spent his career studying complex materials using ultrafast lasers. He did his graduate research at the University of Trieste, Italy, receiving his PhD in 2011. He then took up a postdoctoral position at Lawrence Berkeley National Laboratory. In 2015, he became a staff scientist at SLAC, where he studies high-temperature superconductors using SLAC’s LCLS X-ray laser.

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