Title：A New Approach for the Mesoscopic and Macroscopic Modeling of Quantum Systems: Application in 2D Materials

 Invited Speaker：Dr. Shengjun Yuan

                                  Institute for Molecules and Materials

                                   Radboud University, Nijmegen, the Netherlands

Room：Chemistry Building A717 Hall

Time：10:30 am, June 13, 2016

Abstract：

The deep understanding of the physical properties of 2D materialsrequires the study crossing over from microscopic to macroscopic. New quantum phenomena emerge atthe mesoscopic and macroscopic level, such as interference effects, quantum confinement effects, and charging effects. For structures with scales larger than 100 nanometers, the ab initio calculations are unfeasible. Tight-binding propagation methods (TBPMs) are developed for the modeling of systems range from mesoscopic to macroscopic level, and applied for the calculations of electronic, transport and optical properties. We will give a brief introduction of the methods, and show their applications together with our recent progresses in the study of  2D materials, heterostructures and superstructures, such as the many-body enhancement of insulating states at the additional Dirac points in graphene-hBN heterostructures, the modification of optical gap in fluorographene due to (super)structure disorders, effects of disorder in the electronic and optical properties of semiconducting black phosphorus [8-9] and transition metal dichalcogenides, a new tight-binding model parametrization for black phosphorus with an arbitrary number of layers, quantum Hall effects in biased black phosphorus, and conductance fluctuations in novel 2D fractals. We will also show how to combine the TBPMs with other well-known numerical methods such as DFT-GW and molecular dynamics, and discuss briefly the extension to many-body problem.