Assistant Professor,  University of São Paulo, São Paulo, Brazil.
Physics Institute,  Department of Applied Physics
Phone: +55 11 3091 70 70
Email: fgarcia-at-if.usp.br

Research interests
X-ray spectroscopy of quantum materials
  • Magnetism and structure in itinerant magnets
  • Magnetism and structure in frustrated magnets

2017 - PIBIC - Nosso grupo est
á recrutando estudantes interessadxs em projetos experimentais e teóricos. Veja aqui possíveis  projetos!

2016 - New papers

           Energy scales in a Kondo insulator

            The Kondo effect is a key phenomenum  in condensed matter physics. Its main characteristic is the screening of local magnetic moments by  itinerant electrons. This process is usually understood in terms of both local and many body energy scales. The many body nature of the Kondo effect is specially manifested in the presence of a Kondo lattice, which is formed when the Kondo ion is not only an impurity in the system but is actually  part of a dense lattice of Kondo acitive ions.

             In our recent paper, we investigated spectroscopic properties of the CeFe4P12 Kondo lattice system.  CeFe4P12 is a particularly interesting kind of Kondo system: it is a Kondo insulator, which are systems for which  the exchange interaction between the Kondo ions and the itinerant subsystem is strong enough as to "break" the Fermi surface. Therefore, below a certain coherence temperature, Kondo insulators develop a gap at the Fermi level, whereas at high temperatures this gap is closed. As a consequence, Kondo insulators display an electronic structure which is strongly temperature dependent.

              Our experiments, along with a many body theoretical model, show a way to determine both local and many body energy scales in Kondo insulators. Furthermore, we give clear evidence for valence fluctuations of the Kondo ion in this particular Kondo lattice.

             P. A. Venegas, F. A. Garcia, D. J. Garcia, G. G. Cabrera, M. A. Avila, C. Rettori - "Collapse of the Gd3+ ESR fine structure throughout the coherent temperature of the Gd-doped Kondo Semiconductor CeFe4P12",  Phys. Rev. B 2016 (arXiv:1607.04620).


2014 - present - Assistant Professor - University of São Paulo, São Paulo, Brazil
2012 - 2014 - Pos-doc researcher - UNICAMP, Campinas, Brazil
2011 - 2012 - Pos-doc researcher - Max Plack Institute - CPFS,  Dresden, Germany

2007 - 2010 -  Doctor of Sciences - UNICAMP, Campinas, Brazil

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