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Doctoral thesis
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Infared magneto-optical spectroscopy of boron nitride encapsulated graphene

Defense date2018-10-09
Abstract

The goal of this work is measuring magneto-optical spectra of high quality graphene crystals in the terahertz and infrared regions in order to understand magneto-optical phenomena in graphene unperturbed by defects, impurities, inhomogeneities of chemical potential, etc. For this purpose we used scotch-tape exfoliated hBN-encapsulated graphene membranes suspended over circular apertures of a few dozens of microns in diameter. In order to enable measurements on such small samples, we developed a compact superconducting magnet compatible with commercial FTIR spectrometers and infrared microscopes. Our experiments revealed large magnitudes of the magneto-optical effects: magneto-absorption of circularly polarized light approaching the 50% limit valid for ultrathin conducting films, full magnetic circular dichroism, Faraday rotation angle up to 9°, as well as efficient tunability of these effects with the help of the external magnetic field. Apart form that, we also registered a number of subtle puzzling effects incompatible with a simple single-electron theory.

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Keywords
  • Graphene
  • HBN-encapsulation
  • Hexagonal boron nitride
  • Magneto-optics
  • FTIR
  • Faraday rotation
  • Magnetic circular dichroims
  • Superconducting magnet
  • Kramers-Kronig analysis
  • Landau levels
Research group
Citation (ISO format)
NEDOLIUK, Ievgeniia. Infared magneto-optical spectroscopy of boron nitride encapsulated graphene. 2018. doi: 10.13097/archive-ouverte/unige:114899
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