Two novel stable phases of polonium oxides from first-principles evolutionary algorithm

作     者：Menad, A. Zaoui, A. Ferhat, M. 

作者机构：LPMF Univ Sci & Technol Oran Dept Genie Phys Oran Algeria Ecole Normale Super Mostaganem Dept Phys Mostaganem Algeria Univ Artois Univ Lille IMT Lille Douai JUNIAULR 4515 LGCgELab Genie Civil & Geoenvironm F-59000 Lille France 

出 版 物：《COMPUTATIONAL CONDENSED MATTER》 (Comput. Condens. Matter)

年 卷 期：2024年第40卷

学科分类：07[理学] 0702[理学-物理学] 

主　　题：Bulk crystal phases of polonium oxide (Po-O) system DFT Evolutionary algorithms 

摘      要：Oxygen prominently displays a strong propensity to efficiently form stable molecules by establishing ionic/covalent bonds with a broad array of elements within the Mendeleev Table. That gives rise to a diverse spectrum of oxides that hold pivotal significance in contemporary optoelectronics, mineralogy, biological entities, and atmospheric constitution. We explore here the feasibility of polonium-oxygen compound formation, employing a first-principle evolutionary algorithm. The obtained structural predictions yield two distinct phases of PoO2, exhibiting respectively thermodynamic stability and metastability, specifically the cubic (Fm 3 m) and orthorhombic (Pmn21) crystal structures. Phonon calculations have unequivocally substantiated the dynamical stability inherent in these PoO2 structures. The Po-O system, characterized by its unusual physical-chemical attributes, presents noteworthy features in electronic behavior, bonding interactions, and dynamical properties. Both the Fm 3 m and the Pmn21 phases exhibit semiconductor behavior, each displaying a relatively substantial indirect bandgap of 2.11 eV and 2.50 eV, respectively, within the cubic and orthorhombic crystals. To unravel the bonding nature of PoO2, we employ a suite of analytical tools, including electronic density of states, Bader charge analysis, and electron localization function. These analyses collectively unveil a transfer of electrons from polonium to oxygen, thereby elucidating the coexistence of significant ionic and partial covalent Po-O bonds within the Po-O system.