Riccardo was awarded for his presentation “Charge density fluctuations rule the transport in HTS cuprates". In 2016, he defended his thesis "YBa2Cu3O7‐δ nanowires to study nanoscale ordering in
High-Tc Superconductors" at MC2. Since then he has been a postdoc researcher at QDP. We got the opportunity to ask Riccardo a few questions.
Congratulations to the Young Researchers Award, Riccardo! How does it feel?
"Of course I'm very happy. And proud, since I've been awarded for one of the activities I started from scratches in the framework of my VR International Postdoc, in collaboration with the Politecnico di Milano. In particular, during this postdoc I took a leap in the dark, moving my research activities from transport (my "comfort zone" during the PhD) to spectroscopy and synchrotron-based techniques. Being awarded at the "Spectroscopies in Novel Superconductors" conference, where leading experts in spectroscopy met to address current issues in the frontier of superconductivity research, was very rewarding", says Riccardo.
Tell us a bit about the award!
"The contest was open to all the PhD students and postdocs enrolled in the conference. We have been judged by a committee, evaluating us for both a short oral presentation and a poster presentation. Mine was titled "Charge density fluctuations rule the transport in HTS cuprates". As a winner, I received a printed certificate and a monetary award."
What was your presentation about?
"I presented my work on charge density fluctuations, a new phenomenon - inherent in high critical temperature superconductors - which I recently discovered by means of X-ray scattering. The charge density in this special class of superconductors is already well-known to be non-uniform in space: the valence electrons tend to segregate into periodically modulated structures ("waves"), leading to the formation of a peculiar charge order. Until now such property was believed to influence very little the unusual properties of these materials, since it has been consistently observed only at relatively low temperatures (below 170-200 K)", explains Riccardo.
"What I discovered now, and presented at the conference, is that a periodically modulated charge segregation phenomenon ("charge density fluctuations") is present from low temperatures up to room temperature and beyond, though with characteristics a bit different from those of charge density waves. Being so pervasive, these charge density fluctuations are considered a crucial ingredient - according to some theoretical proposals - to explain the normal state of high critical temperature superconductors, which is a mystery since the discovery of this class of materials more than thirty years ago. The results of this research, which has been led in Milano, in joint collaboration with the ESRF synchrotron in Grenoble, where the X-ray scattering measurements have been performed, with Chalmers University and the Federico II University of Napoli, providing the samples, and with the La Sapienza University of Rome, providing theoretical support, will be published soon in Science."
I hear this is not your first award!?
"Well, that's true...it's the third award I receive! During my PhD, I've been awarded with the ESAS Young Researcher Prize, at the European Conference for Applied Superconductivity 2013, and with the Best Student Paper Award, at the Applied Superconductivity Conference 2014. But - for the reasons I mentioned before - this award is like the first time: that's not simply an expression!"
Tell us a bit about yourself!
"I was born in 1985 in Napoli, Italy, where I lived until 2009, when I received the M. Sc. degree in Physics from the Federico II University. I moved then in Sweden, where I did my PhD at Chalmers, in Floriana Lombardi and Thilo Bauch’s group, working mainly on transport in high-critical temperature superconducting materials and nanodevices. After the PhD, I received an International Postdoc Grant from the Swedish Research Council. This grant is giving me the chance to perform research in a group, headed by Prof. Giacomo Ghiringhelli at the Physics Department of the Politecnico di Milano, with a recognized world leadership in the development of resonant inelastic x-ray scattering (RIXS), an energy loss spectroscopy making use of X-rays to study the spectra of orbital, magnetic, charge and lattice excitations in cuprates and other correlated materials. I'm currently involved in several projects, mainly regarding high-critical temperature superconducting materials, and I perform the experiments in numerous European synchrotrons, as ESRF (Grenoble), Diamond Light Source (Oxford), BESSY II (Berlin) and FERMI (Trieste)," concludes Riccardo.
Text: Michael Nystås
Photo: Flavia Tizzano