Effect of the s ,p-d exchange interaction on the excitons in ZnCoO epilayers
- Others:
- Laboratoire de Spectrométrie Physique (LSP) ; Université Joseph Fourier - Grenoble 1 (UJF)-Centre National de la Recherche Scientifique (CNRS)
- Institute of Experimental Physics [Warsaw] (IFD) ; Faculty of Physics [Warsaw] (FUW) ; University of Warsaw (UW)-University of Warsaw (UW)
- Laboratoire Louis Néel (LLN) ; Centre National de la Recherche Scientifique (CNRS)
- Centre de recherche sur l'hétéroepitaxie et ses applications (CRHEA) ; Université Nice Sophia Antipolis (1965 - 2019) (UNS) ; COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Centre National de la Recherche Scientifique (CNRS)-Université Côte d'Azur (UCA)
Description
We present a spectroscopic study of ZnCoO layers grown by molecular beam epitaxy on sapphire substrates. ZnCoO is commonly considered as a promising candidate for being a Diluted Magnetic Semiconductor ferromagnetic at room temperature. We performed magneto-optical spectroscopy in the Faraday configuration, by applying a magnetic field up to 11T, at temperatures down to 1.5K. For very dilute samples (x<0.5%), the giant Zeeman splitting of the A and B excitons is observed at low temperature. It is proportional to the magnetization of isolated Co ions, as calculated using the anisotropy and g-factor deduced from the spectroscopy of the d-d transitions. This demonstrates the existence of spin-carrier coupling. Electron-hole exchange within the exciton has a strong effect on the giant Zeeman splitting observed on the excitons. From the effective spin-exciton coupling, =0.4eV, we estimate the difference of the exchange integrals for free carriers, N0 |alpha - beta|=0.8=eV. The magnetic circular dichroism observed near the energy gap was found to be proportional to the paramagnetic magnetization of anisotropic Co ions even for higher Co contents.
Abstract
International audience
Additional details
- URL
- https://hal.archives-ouvertes.fr/hal-00021923
- URN
- urn:oai:HAL:hal-00021923v1
- Origin repository
- UNICA