Innovative Computer Modeling of Materials (ICMM)
ICMM's research area is the atomistic modeling and computer simulation of materials systems, particularly the development of multiscale methods to span both length and time scales. Most conventional fully-atomistic methods like molecular dynamics (MD) suffer from the great difference in length and time scales between the atomic-scale processes comprising the materials system and the macroscopic real-life processes, and the multiscale methods are the attempts to bridge this gap.
In particular, to increase the time scales accessible to conventional MD simulation, which are limited to sub-microseconds, I have used hyperdynamics. My current interest in this direction is to devise a novel bias potential for the hyperdynamics simulation that is both computationally inexpensive and robust. In spatial multiscale modeling, I have used the quasicontinuum (QC) method. In particular I have developed "hyper-QC" that can simultaneously span both length and time scales by combining hyperdynamics and QC. Hyper-QC enables to simulate larger systems for longer durations than fully-atomistic unaccelerated models and hence has the broadest impact on any sub-field of materials modeling. Among many potential applications, I am particularly interested in simulating atomic force microscope (AFM) experiments to study atomic-scale friction. Atomic-scale friction exhibits very different characteristics from that in macroscopic systems and has been widely investigated as nanotechnology advances. Especially preventing wear and adhesion is one of the most critical issues in the performance and fabrication of micro/nano-electromechanical systems (MEMS/NEMS) devices. Friction and wear of biomaterials are also investigated using AFM. My current goal in this direction is to simulate realistic AFM models under experimental conditions using the hyper-QC method.
- NSF CMMI-1662666: Accelerated Molecular Dynamics Study of the Role of Crystalline Defects in Friction of 2-Dimensional Materials, July 1, 2017 - June 30, 2020
- NSF CMMI-1463038: Accelerated Large-Scale Simulation Study of Atomic-Scale Wear Using Hyper-QC, July 1, 2015 - June 30, 2018