报告人：汪林望

报告题目：Large scale atomistic material simulations:the challenges and opportunities.

报告摘要：The ab initio material simulation based on quantum mechanics has been developed for more than forty years. With the maturity of the methods, the developments of user friendly codes, and the increase of high performance computer power, the atomistic ab initio methods, especially the methods based on density functional theory, have been used in every aspects of material researches. It is now a common practice to simulate systems with hundreds of atoms. However, since the computational cost scales as the third power of the number of atoms, new strategies are needed to go beyond this barrier. Furthermore, hug gap exists between the computable systems and many of the experimental systems, both in size scale and temporal scale. How to bridge this gap is a main challenge in order to bring the ab initio computation into industry. To overcome such challenges, we need to use multiple methods, including linear scaling method, machine leaning method, as well as kinetic Monte Carlo schemes to overcome the time scales.

报告简介：Chief scientist in Semiconductor Institute, CAS, and chief scientific advisor in LongXun Kuang Teng Inc. Senior Staff Scientist, Lawrence Berkeley National Laboratory, Berkeley, CA, U.S. 1999-2021. Dr. Wang has 30 years of experience in large scale electronic structure calculations. He has worked in O(N) electronic structure calculations in early 1990s. Worked with Alex Zunger, he invented the folded spectrum method which pushed the limit of nonselfconsistent electronic structure calculations from 100 atoms to thousands of atoms. He developed a linear combination of bulk bands (LCBB) method for semiconductor heterostructrure electronic structure calculations, which allows the calculation of million atom devices. He developed generalized moments method which calculates the density of state and optical absorption spectra of a given system without explicit calculation of its eigenstates. He also developed a popular parallel total energy plane wave pseudopotential program (PEtot). He invented a charge patching method, which enables the ab initio accuracy thousand atom calculations for nanosystems. He has developed a linear scaling three dimensional fragment method (LS3DF), which can be used to selfconsistently calculate systems with tens of thousands of atoms. Recently, he developed a new algorithm for real-time time-dependent DFT calculations which accelerates the traditional algorithms by hundreds of times.