Dr. Eduardo Bonini Guedes
Spectroscopy of Novel Materials Group
5232 Villigen PSI
Eduardo Bonini Guedes received his PhD in 2017 from Universidade Federal do Parana - Brazil, where he worked under Prof. Rodrigo Mossanek, performing x-ray photoemission and absorption spectroscopies as well as ab-initio and cluster model calculations on Ru-based perovskites. He joined SIS beamline in 2017.
Dr. Guedes conducts research within the Spectroscopy of Novel Materials group and provides operational support to users of COPHEE endstation.
Dr. Guedes' research focuses on spin- and angle-resolved photoemission investigations of titanates and other systems showing a 2-dimensional electron gas at is surface. For this end he primarily uses in-situ sample growth via pulsed laser deposition (PLD) and both COPHEE and ULTRA endstations.
Role of Ti-Ru interaction in SrTi0.5Ru0.5O3: physical properties, x-ray spectroscopy, and cluster model calculations, Guedes EB, Abud F, Martins HP, Abbate M, Jardim RF, Mossanek RJO, Physical Review B. 100, 075132 (2019)
We have performed a systematic study of the physical properties and electronic structure of SrTiO3, SrTi0.5Ru0.5O3, and SrRuO3. For the mixed compound, the temperature dependence of the magnetization is consistent with the occurrence of RuTi and TiRu defects. Despite being a semiconductor, the behavior of the electrical resistivity as a function of temperature is compatible with the emergence of small metallic regions richer in Ru concentration, a feature supported by the finite spectral weight at the Fermi level observed in the valence-band x-ray photoemission spectroscopy spectrum. The x-ray photoemission and absorption spectra of the SrTi0.5Ru0.5O3 compound were simulated by double cluster model calculations, which include the TiO6-RuO6 interaction, and also by the linear combination of single cluster calculations for SrTiO3 and SrRuO3. The results indicate that the interaction between different octahedra may give rise to distinct peak characters, depending on the experimental spectrum being calculated. We argue that these effects are only captured with the explicit inclusion of the Ti-Ru interaction.
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