Physikalisches Kolloquium

Physics Colloquium at The Faculty of Mathematics and Natural Sciences

Lectures on tuesdays 16:15pm in Hans-Geiger auditorium

Leibnizstr. 13, 24098 Kiel

 

Sommersemester 2020

 

INFO: Leider können durch die Corona-Situation im Sommersemester keine Präsenzveranstaltungen stattfinden!

 

  • 07.04.2020:

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  • 14.04.2020:

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  • 21.04.2020: Dr. James McIver (CFEL Hamburg) FÄLLT AUS

    Titel: Femtosecond science on-chip: Capturing light-induced anomalous Hall currents in graphene

    Abstract: Many non-equilibrium phenomena have been discovered or predicted in quantum solids driven by femtosecond pulses of light. Examples include photo-induced superconductivity [1] and Floquet-engineered topological phases [2]. These effects are expected to lead to measurable changes in electrical transport. However, the timescales involved far exceed those accessible using conven-tional fast electronics. In this talk, I will present results on the transport properties of monolayer gra-phene illuminated by a femtosecond pulse of circularly polarized light [3]. This was achieved using an ultrafast device architecture based on laser-triggered photoconductive switches. We observed a light-induced Hall effect in the absence of an applied magnetic field. The dependence of the effect on a gate potential used to tune the Fermi level revealed multiple features that reflect a Floquet-engineered topological band structure, similar to the band structure originally proposed by Haldane [4]. This includes a ~60 meV wide conductance plateau centered at the Dirac point, where a gap of equal magnitude is predicted to open based on Floquet theory. We find that when the Fermi level lies within this plateau, the non-equilibrium anomalous Hall conductance saturates around ~1.8+/-0.4 e^2/h.

    References:
    [1] D. Fausti et al. Science 331, 189-191 (2011)
    [2] T. Oka & H. Aoki. Phys. Rev. B 79, 081406 (2009)
    [3] J.W. McIver et al. Nature Physics 16, 38-41 (2020)
    [4] F.D.M. Haldane, Phys. Rev. Lett. 61, 2015-2018 (1988)

    Gastgeber: Prof. Bauer
  • 28.04.2020: Prof. Dr. Alexander Khajetoorians (Radboud Universität, Nijmegen) FÄLLT AUS

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    Gastgeber: Prof. Heinze
  • 05.05.2020: Prof. Dr. Peter Hommelhoff (Friedrich-Alexander-Universität Erlangen-Nürnberg) FÄLLT AUS

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    Gastgeber: Prof. Bauer
  • 12.05.2020: Prof. Dr. Harald Gießen (Director of Physics Institute IV, University of Stuttgart) FÄLLT AUS

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    Gastgeber: Prof. Talebi
  • 19.05.2020:

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  • 26.05.2020: Prof. Ulrich Hohenster (Institut für Physik, Karl-Franzens-Universität Graz) FÄLLT AUS

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    Gastgeber: Prof. Talebi
  • 02.06.2020:

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  • 09.06.2020:

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  • 16.06.2020: Prof. Sunil Sinha (UC San Diego) FÄLLT AUS

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    Gastgeber: Dr. Bridget Murphy
  • 23.06.2020: Prof. Eric Becklin (UCLA), Chief Science Advisor des SOFIA-Telescopes FÄLLT AUS

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    Gastgeber:Prof. Duschl
  • 30.06.2020:

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  • 07.07.2020:

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  • 14.07.2020:

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