# Spectroscopies sous haute pression et champ magnétique intense

Abstract : This PhD thesis presents some optical spectroscopy measurements under extreme conditions of pressure and high magnetic field at low temperature. The main objective of this work was to develop a new setup allowing to combine these outstanding extreme conditions. We have successfully extended the experimentally achievable phase diagram area up to 56 T, 10 GPa and 4 K. We have then studied two kinds of system to demonstrate the interest of our new technique: transition metal ions and semiconductors. We have first measured by magneto-photoluminescence experiments at high field on ruby the Zeeman effect, i.e the lift of spin degeneracy and the Paschen-Back effect, due to the competition between the anisotropic crystal field and the applied magnetic field. We unveiled and explained a significant increase of the trigonal component induced by the pressure. We have also investigated the electronic structure of indium selenide, a layered semiconductor with noteworthy excitonic properties by magneto-absorption spectroscopy. Oscillatory magneto-absorption unraveled the electrons and holes Landau quantization, allowed us to deeply probed the band structure in a wide energy range around the direct gap and to confirm the validity of the specific $k.p$ model for this compound. Eventually, magneto-photoluminescence measurements on self-assembled indium phosphide quantum dots embedded in a gallium phosphide matrix yielded us to elucidate the origin of the strong luminescence observed in this material. We have determined the confinement of the charge carriers and clarified the effects of the native biaxial strain.
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Cited literature [122 references]

https://tel.archives-ouvertes.fr/tel-00436291
Contributor : Marius Millot <>
Submitted on : Thursday, November 26, 2009 - 11:47:44 AM
Last modification on : Friday, July 10, 2020 - 7:58:43 AM
Long-term archiving on: : Tuesday, October 16, 2012 - 2:55:37 PM

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• HAL Id : tel-00436291, version 1

### Citation

Marius Millot. Spectroscopies sous haute pression et champ magnétique intense. Matière Condensée [cond-mat]. Université Paul Sabatier - Toulouse III, 2009. Français. ⟨tel-00436291⟩

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