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12 September 2019: 2 events

séminaire

  • Electronic properties and electronic dynamics in topological semimetals

    Thursday 12 September 11:00-12:00 - Alberto Crepaldi - EPFL

    Electronic properties and electronic dynamics in topological semimetals

    Résumé : Since the discovery of topological insulators, the field of topological materials has attracted increasing attention in the condensed matter community [1]. On the one hand, the high mobility and the spin polarization of the states at the Fermi level make those compounds promising for applications. On the other hand, the low-energy electronic properties of those materials realize exotic quasiparticles, which were only postulated in high-energy physics (Dirac and Weyl Fermions) [2, 3]. Angle-resolved photoelectron spectroscopy (ARPES) has proven to be a powerful tool to directly resolve the signature of these different topological phases. In this talk I will provide a summary of my research activity of the last years. I will introduce the concept of topological semimetals, focusing on the protection and stability of the 3D Dirac semimetal phase [4-6]. By exploiting the capability of time-resolved ARPES to study the band structure upon excitation of electrons in the unoccupied conduction band, I will show you that the electron dynamics is sensitive to the formation of Weyl points [7], and that the material band dispersion can be modified by varying the electronic screening [8].
    [1] M. Z. Hasan and C. L. Kane, Rev. Mod. Phys. 82, 3045 (2010)
    [2] N. P. Armitage et al., Rev. of Mod. Phys. 90, 015001 (2018)
    [3] B. Bradlyn et al., Science 353, 6299 (2016)
    [4] G. Manzoni et al., PRL 117, 237601 (2016)
    [5] S. Roth et al., PRB 97, 165439 (2018)
    [6] A. Crepaldi et al., Phys. Rev. B 95, 041408(R) (2017)
    [7] A. Crepaldi et al., Phys. Rev. B 96, 241408(R) (2017)
    [8] G. Gatti et al., in preparation.

    Lieu : Moyen Amphi RDC @ LPS, bât 510

    En savoir plus : Electronic properties and electronic dynamics in topological semimetals
  • Voyage vers la lune : de la fiction à la réalité -Roland Lehoucq

    Thursday 12 September 13:30-15:00 - Roland Lehoucq - IRFU, CEA Saclay

    Voyage vers la lune : de la fiction à la réalité

    Lieu : Orsay - Cité universitaire - LPS, Bât 510 amphi Blandin

    En savoir plus : Voyage vers la lune : de la fiction à la réalité -Roland Lehoucq