Colóquio de Física

  • Responsável: PPG-FIS
  • Câmpus: Santo André
  • Local: Auditório 111-0, Bloco A, Santo André
  • Data: 20/03/2019
  • Horário: 14:00 às 16:00
  • Descrição:

    Colóquio de Física
    Palestrante: Prof. Dr. Marcos Pimenta (Dep. de Física – UFMG)
    Título: “Probing electrons, phonons and electron-phonon interactions in two-dimensional (2D) materials by Raman spectroscopy”
    Resumo: The pioneering experiments with graphene in 2004 opened a new area of research in science, which is the study of two-dimensional (2D) crystals. The behavior of the electrons in these materials depends not only on the atomic and crystalline structure, but also on the number of layers and the stacking order between layers. For example, the electronic structure of bilayer graphene depends strongly of the twisting angle between the layers. Several new 2D systems have also been produced and studied, including an allotrope form of phosphorus, called black phosphorus, and the semiconducting transition metal dichalcogenides MX2(M = Mo, W and X = S, Se, Te). In this presentation, I will first discuss how Raman spectroscopy provides information about electrons, phonons and their interactions in 2D materials. I will present a Raman study on black phosphorus edges that show the appearance of edge phonons, and theoretical simulations confirm that they are originated by the atomic rearrangements at the crystalline terminations [1]. I will then present a multiple excitation Raman study in MoS2, where we could evidence electron scattering processes by acoustic phonons between different valleys in the electronic structure [2]. I will present results in twisted bilayer samples and graphene on the top of h-BN and show the ability of Raman spectroscopy to probe and distinguish interlayer and intralayer electron-phonon interactions in graphene heterostructures [3].

    1. H. B. Ribeiro et al, Nature Comm. 7, 12191 (2016)
    2. B. R. Carvalho et al. Nature Comm. 8, 14670 (2017)
    3. G. S. N. Eliel et al. Nature Comm. 9, 1221 (2018)

  • Necessita inscrição: Não
  • Link de divulgação: http://fisica.ufabc.edu.br/index.php/coloquios

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