Prediction of HfB3 from first-principles calculations: crystal structures, stabilities, electronic properties and hardnesses. (4th March 2019)

• Record Type: Journal Article
• Authors: Huang, Lan-Hui; Zhao, Ya-Ru; Zhang, Gang-Tai; Zhang, Mei-Guang; Li, Pei-Ying; Hu, Yan-Fei
• Is Part Of: Molecular physics. Volume 117:Number 5(2019)
• Page Start: 547
• Page End: 556
• Publication Date: 2019-03-04
• Subjects: Structure prediction -- HfB3 -- superhard materials -- electronic properties; Molecules -- Periodicals; Chemistry, Physical and theoretical -- Periodicals; Molécules -- Périodiques; Chimie physique et théorique -- Périodiques; 539.6.05
• DOI: 10.1080/00268976.2018.1527047
• Languages: English
• ISSNs: 0026-8976

Abstract

ABSTRACT: First-principles calculations combined with particle swarm optimisation technique are employed to provide an in-depth understanding of the structures, stabilities, electronic properties, and hardnesses for hafnium triboride. Three novel structures of HfB3 with C2/ m, Cmmm, and Pmma phases are predicted under the ambient pressure. The new phases are energetically much superior to the previously proposed m-AlB2 -, and TMB3 -type (TM = W, Mo) structures. The mechanical and thermodynamic stabilities of the new structures are confirmed by the elastic constants and formation enthalpies. The phonon dispersion curves reveal that they are dynamic stable. The large bulk, shear modulus, and small Poisson's ratio of the C2/ m and Pmma phases, make them the promising high incompressible materials. It is worth mentioning that the considerable hardness of 40.8 GPa testifies the most stable C2/ m -HfB3 to be considered as a potential superhard material. On the basis of the electronic density of states and chemical bonding analysis, one can find that the strong B–B and Hf–B covalent bonds are present in HfB3 compounds. Particularly, higher incompressible and hardness of the C2/ m -HfB3 may also relate to its stacking of 'sandwiches' structure. GRAPHICAL ABSTRACT: