Multiscale Computational Physics Lab

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Welcome to Multiscale Computational Physics Lab

We develop fundamental theories and utilize simulation based experiments for different physical problems across different time/length scale and their applicaitons

We will publish interesting and cutting edge research results here. Stay Tune!

May 15, 2015: Introduction to Multiscale Modeling

Nanoelectrodynamics

The electrical phenomenon are very differant from what we observe in marco scale. Various experimental approaches have been developed for harvesting energy from the environments based on thermoelectricity and piezoelectricity. Innovative nanotechnologies have been developed for converting mechanical energy into electric energy experimentally. It is noticed that theoretically, at nanoscale, the physical phenomena cannot be explained by classical continuum physics; instead one should resort to atomistic descriptions. Our Atomistic Field Theory Theory is an atom-embedded theory, which distinguishes crystalline solids from other states of matter by a periodic arrangement of the atoms; such a structure is called a Bravais lattice. Using AFT, we obtain balance of linear momentum. The sourcing term involves contact force (nano-piezoelectricity), body force (nano-ferroelectricity) and temperatre force (nano-thermoelectricity and nano-pyroelectricity). As the solution to the linear momentum, it is the atomic position. The polarization of each unit cell can be easily calculated by the atomic charge and atomic position. Furthermore, the induced electric potential and induced electric field are acquired.

In classical theory, how to relate the displacement to electric polarization is used to be linear theory. In our AFT, the electric polarization, induced electric potential and induced electric field are simultaneously connected with the atomic position as long as the solution to the balcne law of linear momentum is obtained. The computationl scheme (GFEM) has been also developped. It can calculate induced electric field by either all unit cells or representative unit cells depending on the efficiency and user's choice. This theory and computational scheme can serve to study multiscale modeling of electro-mechanical coupling, design nanogenerator and analyze nano piezoelectronicity and nano energy harvesting.