 | Laboratory of Theoretical and Experimental Superconductive Tunnelling |
 | Renato S. Gonnelli
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| Present position | Associate Professor | |||||||||
| Work and research experience |
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| Education |
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| Role and membership in Scientific Committees and Editorial Boards | 2002 Scientific Committee of the International
Conference BOROMAG, Genova, Italy 2002 Scientific Committee of the National Conference SATT 11, Vietri, Italy 2004 Scientific Committee of the International Conference SSSI 04, Smolenice, Slovakia 2004 Scientific Committee of the National Conference SATT 12, Rome, Italy 2005 Scientific Committee of the Internat. Conference WWS2005, Bratislava, Slovakia 2006 Program Committee of the International Conference CIMTEC 2006, Acireale, Italy 2006 Scientific Committee of the National Conference SATT 13, Sestri Levante, Italy 2008 Scientific Committee of the National Conference SATT 14, Parma, Italy 2010 Program Committee of the Int. Conference CIMTEC 2010, Montecatini Terme, Italy 2010 Scientific Committee of the National Conference SATT 15, Alghero, Italy | |||||||||
| International reputation |
My research is mentioned in the entry “La Fisica del Novecento” of the
“Enciclopedia Italiana di Scienze, Lettere ed Arti - Treccani” (Ottava
Appendice) I am author of 8 invited review articles on point-contact Andreev reflection spectroscopy in MgB2, multiband anisotropic superconductors and Fe-based ones. I am referee for several international journals including: Science, Physical Review Letters, Physical Review B, Europhysics Letters, Applied Physics Letters, SUST, etc. | |||||||||
| Affiliation to
Scientific Societies or Associations or Institutes | Since 2012 Member of the National Agency for the Evaluation of Universities and Research Institutes (ANVUR) in GEV 2 (Physical Sciences) area Since 2005 Member of the National Panel for Physics of the National Committee for the Evaluation of the Research (CIVR) Since 2005 Affiliated to the “Consorzio Nazionale Interuniversitario per le Scienze fisiche della Materia” (CNISM) and director of the Research Unit of Politecnico di Torino From 1994 to 2004 Affiliated to the Italian Institute for the Physics of Matter (INFM) | |||||||||
| Summary of Research Activity |
1980-1991 Measure (by means of superconducting instrumentation) and analysis of the weak magnetic fields produced by the human body (biomagnetism). Main results: - first measure of the isofield maps of the cardiac magnetic field in subjects with infarction; - first measure of the magnetic field produced by the isolated heart of a small mammalian (rabbit). 1987-present Point-contact and tunneling spectroscopy, Josephson effect and electron-boson interaction in high-Tc superconductors (HTS), in borocarbides, in ZrB12, in the intermetallic superconductor MgB2 and related compounds, in anisotropic superconductors (CaC6) and in the new Fe-based superconductors. Main results: - First measurements of point-contact tunneling on monophasic samples of the ceramic superconductor YBCO (1987) and on single crystals of BSCO in high magnetic fields (1990) - Determination of the spectral function of electron-phonon interaction in BSCCO by inversion of the Eliashberg equations (1994) - Realization (using a controlled break-junction technique) of non-hysteretic Josephson junctions in BSCCO and BSCO with high critical current values and quality factors (1995) - First measures of non-hysteretic Josephson effect in BSCO (1997) - Experimental study and theoretical modeling of the influence of the surface depression of the order parameter and of its symmetry on the temperature dependence of Josephson critical current in different high-Tc superconductors (1997) - Study of resistivity and electron-phonon coupling in the YNi2B2C borocarbide (2000) - First evidence of the separation between pseudogap and phase-coherence gap in LSCO (2001) - Determination of the gaps in magnesium diboride (MgB2) with unprecedented accuracy by means of directional point-contact spectroscopy in high-quality single crystals in magnetic fields (2002) and verification of the predictions of the two-band model in dirty limit (2004) - Determination of the effects of doping (by Al or C) and co-doping (with Li and Al) on the gaps of MgB2 and their explanation within the Eliashberg theory (2005, 2008, 2009) - Determination of the effects of magnetic (Mn) impurities on the superconducting gaps of MgB2 and interpretation of the results within the Eliashberg theory (2006) - Study of the anisotropy of the superconducting gap in the graphite intercalation compound CaC6 by means of directional point contact spectroscopy in single crystals down to 400 mK (2008) - Early evidence of two isotropic superconducting gaps in LaFeAs(O,F) and SmFeAs(O,F) (2009) - Determination of the energy gaps and identification of the characteristic energy of the electron-boson spectrum by directional point-contact spectroscopy in single crystals of Ba(Fe,Co)2As2: a direct proof of the spin-fluctuation mediated coupling (2010) - Extension of the Blonder-Tinkham-Klapwijk model to account for multiple gaps and non-spherical Fermi surfaces (2011) - First evidence of the emergence of lines of nodes in the gaps of Ca(Fe,Co)2As2 associated to a topological transition of the Fermi surface (2012) - Determination of the effect of doping on the energy gaps of Ba(Fe,Co)2As2 (2013) and Fe(Se,Te) (2014) by means of point-contact measurements in thin epitaxial films - First point-contact measurements under pressure in undoped CaFe2As2: evidence for the connection between topological 2D-3D transition in the Fermi surface and enhancement of the superconducting properties (2014) 2008-present: Electric field-effect doping of thin films of conventional metals and superconductors as well as single-layer and few-layer graphene by means of polymer-electrolyte-solution gating. Main results: - Modulation of the resistance of thin films of metals (Au, Cu, Ag) by means of a transverse electric field in conventional back-gate FET devices on suspended SiN membranes. (2008) - Achievement of unprecedented levels of charge doping (up to 4.5×1015 e/cm2) in Au, Cu and Ag films by means of a suitable polymer electrolyte solution (PES). First observation of a decrease in the resistivity of Au by 10% at low temperature (2012-2013) - Achievement of very high levels of charge doping (up to 6.8×1014 e/cm2) in few-layer graphene devices and study of their particular electric transport properties at low temperature (electron-electron scattering) and very low temperature (weak localization regime). | |||||||||
| Supervision of PhD Students | 2014-2016 Erik Piatti 2012-2014 Kanudha Sharda 2011-2013 Alessandro Sola 2005-2007 Mauro Tortello 2003-2005 Andrea Calzolari 1999-2001 Dario Daghero 1996-1998 Carlo Bravi 1994-1996 Giovanni Ummarino | |||||||||
| Publications | The research
activity described above has produced about 150 articles in peer-reviewed journals or books with
more than 1500 citations (180 the most cited one) and more than 40 invited
talks at international conferences. List of publications (archive of Politecnico di Torino) |
| LaTEST - Department of Applied Science and Technology, Politecnico di Torino corso Duca degli Abruzzi 24, 10129 Torino (TO) - Italy  |