【大学频道】中国科学院大学卡弗里理论科学研究所呈献 | 中国科学技术大学任新国研究员 | 自由微信

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【大学频道】中国科学院大学卡弗里理论科学研究所呈献 | 中国科学技术大学任新国研究员

原创 KouShare 蔻享学术 2021-04-25

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图 | 任新国研究员

题目：Periodic GW and RPA Methods Within A Numeric Atom-centered Basis Set Framework

报告人：任新国

单位：中国科学技术大学

时间：2019-05-30

地点：中国科学院大学

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报告摘要

We have implemented the periodic G⁰W⁰ method for quasiparticle energy calculations and the random-phase approximation (RPA) for ground-state total energy calculations within the all-electron, numerical atomic orbital (NAO) basis-set framework. A straightforward implementation of such correlated methods within the NAO framework is extremely expensive in terms of both the memory demand and CPU times. Here we employed a localized variant of the resolution of identity (RI) approximation, enabling a significant reduction of the computational cost to evaluate and store the two-electron Coulomb repulsion integrals. We demonstrate that the error due to localized RI approximation is controllable and can be made negligibly small by enhancing the set of auxiliary basis functions (ABFs) used to expand the products of two single-particle NAOs. An efficient algorithm, suitable for the NAO framework, has been developed to deal with the Coulomb singularity in the Brillouin zone sampling. We performed systematic convergence tests and identified aset of computational parameters (basis sets, enhanced ABFs, and k-point grid), with which reliable G⁰W⁰ and RPA results can be obtained. Our implementation is carried out within the all-electron, NAO-based software package -- FHI - aims. Benchmark results for 3 - dimensional insulators / semiconductors as well as 2-dimensional materials will be presented.

个人简介

任新国，中国科学技术大学量子信息实验室特任研究员，博士生导师。2006年毕业于德国奥格斯堡大学，获得凝聚态物理博士学位。2006年至2012年在德国柏林弗里兹-哈珀研究所从事博士后研究工作，2013年回国，在中国科大量子信息实验室工作至今。2015年被任命为德国马普学会“先进电子结构方法”马普伙伴小组组长。研究领域包括：密度泛函理论，特别是基于无规相近似的先进交换关联泛函方法；格林函数理论，特别是基于GW近似的激发态计算方法；以及大型第一性原理计算软件的开发。迄今共发表了研究论文近50篇，被引用4000余次。