Jorge Sofo
Jorge Sofo sits in an unassuming office in Osmond Lab connected via a Unix workstation to a parallel computer in Davey Lab containing 100 individual 1.4 GHz Athlon processors with 1.5 GB of RAM each. This kind of high-powered computer is required for the type of work he does: electronic structure calculations. The materials, phenomena and technologies that Sofo investigates vary widely from catalysis to alloy formation to thermoelectrics. What his methods calculate are the energies required to form atoms and molecules. For instance, knowing the total energy or, more specifically, configuration of minimum energy can aid in predicting and understanding a myriad of phenomena including surface mobility, energy barriers and diffusion coefficients.
Computing these energies is a very challenging endeavor requiring a high degree of precision in the computer code. The biggest hurdle is that the energy to "form" a typical atom (i.e., energy required to bring each of the electrons near the nucleus) is on the order of 10,000 eV while the energy required to form a chemical bond between two atoms may be only 5 eV. The code he uses must account for all the energy in the solid and be precise to within 1 eV. Even with the immense computing power in his computer cluster, his simulations generally only comprise 100 atoms or so and may take days to complete.
He is currently collaborating with the Badding group (Chemistry) to predict electrical conductivity, the electronic contribution to thermal conductivity and the Seebeck coefficient for Bi2Te3 thermoelectric materials used as electronic coolers. A collaboration with Tom Mallouk involves calculating the electronic and crystal structure of nitrogen and fluorine substituted perovskites. Sofo is also working with the Castleman group to simulate the structure of molecular clusters. Pictured below is a simulation showing the most stable configuration of an acetone-water cluster. He is also collaborating with Prof. Zi-Kiu Liu to combine ab-initio calculations with Calphad for the determination of phase diagrams.
Jorge Sofo came to Penn State in the fall of 2001 to become the Director of Penn State's new Materials Simulation Center. He came from Argentina where he has been a physics faculty member at his alma mater, Instituto Balseiro since 1995. He spent several summers working with collaborators in Austria and France. Before that he spent four years at Oak Ridge National Lab and as a post doctoral scholar at the University of Tennessee.
