Speaker: Stephan Roche
Affiliation: Catalan Institute of Nanoscience Nanotechnology, Campus UAB, Bellaterra, Spain ICREA, Institució Catalana de Recerca i Estudis Avancats, Spain
Host: Professor Feng Yuan Ping
Location: Click HERE for directions
Abstract Details: I will discuss charge and thermal transport in chemically and structurally complex forms of graphene accounting from substrate effects, polycrystalline morphology of CVD graphene (and h-BN), and chemically functionalization; all aspects being of crucial relevance for the development of applications in flexible and transparent electronics, energy harvesting and spintronics. After introducing some challenges about the modelling of graphene composites I will present some quantitative analysis of charge and thermal transport properties in graphene materials in presence of structural imperfections as produced during the wafer-scale production of graphene through chemical growth (CVD), the chemical transfer to versatile substrates, and the device fabrication. Fundamental properties of charge mobilities in polycrystalline graphene, accounting the variability in average grain sizes and chemical reactivity of grain boundaries as observed in real samples grown by CVD will be presented, together with their relevance for device optimisation and diversification of applied functionalities such as chemical sensing .
The development of multiscale simulation and predictive modelling will be shown to enable simulations of physical properties (dissipative and Hall conductivities and thermal conductance) in realistic models of very large system sizes (reaching easily the 1 billion atoms scale), matching the experimental and technology scales .
 A. Isacsson, A.W. Cummings, L. Colombo, L. Colombo, J.M. Kinaret, S. Roche, 2D Materials 4 (1), 012002 (2016); A.W. Cummings, D. Duong, V. Luan Nguyen, D. Van Tuan, J. Kotakoski, J.E. Barrios Vargas, Y. Hee Lee, S. Roche; Advanced Materials 26, Issue 30, 5079-5094 (2014); M. Seifert et al, 2D Mater. 2, 024008 (2015); D. Van Tuan, J. Kotakoski, T. Louvet, F. Ortmann, J. C. Meyer, S. Roche, Nano Lett. 13, 1730−1735 (2013)
 Z. Fan, J. H. Garcia, A.W. Cummings, J.-E. Barrios, M. Panhans, A. Harju, F. Ortmann, S. Roche, ´Linear Scaling Quantum Transport Methodologies´, arXiv:1811.07387 (accepted for publication in Review of Modern Physics). LEFF Torres, S. Roche, J.C. Charlier, ´Introduction to graphene-based nanomaterials: from electronic structure to quantum transport´, Cambridge University Press (2014)
About the Speaker: Prof. Stephan Roche is a theoretician with more than 25 years' experience in the study of Condensed Matter physics and particularly the transport theory of low-dimensional systems, including graphene and two-dimensional materials, carbon nanotubes, semiconducting nanowires, organic materials, quasicrystals, DNA and topological insulators. After serving as assistant Professor at the Université Joseph Fourier-UJF, and as a staff researcher of the Commissariat à l´Energie Atomique (Grenoble, France), he became ICREA Research Professor in 2010 and since then he is leading the “Theoretical and Computational Nanoscience” group at the Catalan Institute of Nanoscience and nanotechnology (ICN2), a flagship institute of the member of the Barcelona Institute of Science and Technology (BIST). He studied theoretical physics at Ecole Normale Supérieure (Lyon-France) and got his PhD at UJF. He has worked in France, Japan, Germany and Spain.
He has published about 200 papers in scientific journals and is the co-author of “Introduction to Graphene-Based Nanomaterials: From Electronic Structure to Quantum Transport” (Cambridge University Press, 2014) as well as the co-Editor of “Topological Insulators, Fundamentals and Perspectives” (WILEY 2015), and “Understanding carbon nanotubes: from Basics to Applications” (Lectures Notes Phys. Springer 2006). He has served as member of the Editorial Boards of 2D Materials (IoP) and the Rivista Nuovo Cimento (Italian Physical Society) for the past 4 years, and he is Chief Editor of Journal of Physics Materials (IoP) since early 2018. In 2009 he was awarded the Friedrich Wilhelm Bessel Research Award by the Alexander Von-Humboldt Foundation (Germany) in recognition of his outstanding contributions to the field of Computational Nanosciences. Since 2011 he has been actively involved in the European Graphene Flagship project, and currently appointed as the deputy leader of the spintronic work package.