Ga掺杂δ-Pu的密度泛函理论计算

doi:10.19596/j.cnki.1001-246x.7673

摘要/Abstract

摘要： δ-Pu为Pu的高温相，掺杂少量的Ga即可使其在室温下稳定存在.本文采用密度泛函理论方法，对不同掺杂量体系进行晶体结构和电子结构计算，主要包括体系的晶格常数、密度、形成能、态密度、电荷密度和Mulliken布居分析.结果表明：在研究范围内，Ga掺杂后，体系晶格常数降低，密度增大，6.25%（原子百分比，下同）掺杂量体系的稳定性高于3.125%和12.5%掺杂量的体系；Ga掺杂使得Pu周围体系电子的局域性增强，成键能力增强，揭示了Ga稳定δ-Pu的电子机制.Ga和Pu之间为金属键，发生的作用主要由Pu的7s、6p、6d和Ga的4s、4p轨道电子贡献，但这种成键作用相对较弱，使得掺杂体系可以保持原有的力学性能和机械加工性能.Ga对δ-Pu的稳定作用主要在于改善Pu原子的成键性能，而不是与Pu原子直接成键.

关键词: Ga掺杂, δ-Pu, 晶体结构, 电子结构, 密度泛函理论

Abstract: As a high-temperature phase of Pu, δ-Pu doped with little Ga can stay to room temperature. Crystal structure and electronic structure of systems with different contents of Ga are calculated with density functional theory (DFT) method. Calculations mainly include lattice constant, density, formation energy, density of states(DOS), electron density and Mulliken population. It shows that within studied doping scope, lattice constant of systems decrease and density of systems increase with increase of content of Ga, while stability of system with 6.25% content of Ga is superior to that with 3.125% and 12.5% content of Ga. Ga-doping enhanced locality and strengthens bonding ability of electrons, which, to some degree, reveals electronic mechanism of Ga stabilizing δ-Pu. Character of Pu-Ga bond is metallic state, and interaction is mainly contributed by Pu 7s, 6p, 6d and Ga 4s, 4p orbital electrons. While interaction is relatively weak, doped systems maintain fine mechanical properties and machining performance. Contribution of Ga to stability of δ-Pu lies mainly in its improvement on bonding performance of Pu, instead of its immediate bonding effect with Pu.

Key words: Ga-doping, δ-Pu, crystal structure, electronic structure, density functional theory

中图分类号:

O641

李大伟, 高云亮, 朱芫江, 李进平. Ga掺杂δ-Pu的密度泛函理论计算[J]. 计算物理, 2018, 35(4): 487-493.

LI Dawei, GAO Yunliang, ZHU Yuanjiang, LI Jinping. Density Functional Theory Calculations of Ga Doped δ-Pu[J]. CHINESE JOURNAL OF COMPUTATIONAL PHYSICS, 2018, 35(4): 487-493.

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