Computational Math Reports——Electronic structure calculations for metallic systems
主 题: Computational Math Reports——Electronic structure calculations for metallic systems
报告人: Xingyu Gao (Institute of Applied Physics and computational Mathematics)
时 间: 2017-11-16 15:00-16:00
地 点: Room 1479, Sciences Building No. 1
Abstract: It is a usual practice to calculate the occupied orbitals for semiconducting, insulating or isolated systems. It differs significantly in metallic systems and partial occupancies have to be included at the same time. In the language of optimization, this is an ill-conditioning problem with partial occupancies treated as additional variational degrees of freedom. We will find the origin of the conditioning problem related to metallic systems and discuss specific strategies for it. An alternative approach is the self-consistent iteration. One reason why the self-consistent schemes are efficient lies probably in the fact that both subproblems can be preconditioned well with plane wave basis. Combining our recent work, we would like to share our understanding of the preconditioning techniques. Besides, we will introduce some computational issues of our concern, such as optimization of atomic positions and modeling of disordered matter.