New ultra-incompressible phases of NbB4 predicted from first principles

Li, Xiaofeng; Han, Liang; Hou, Yunshan; Yan, Haiyan; Hu, Ziyu; Zhang, Shengli

doi:10.1016/j.physleta.2016.11.001

Cited by 8 publications

(1 citation statement)

References 35 publications

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“…However, the later studied results have shown that the hexagonal WB4 phase is instable and it is actually WB3 with a MoB3-type structure [16][17][18][19]. Theoretically, based on the crystal structure search code and first-principles calculations, the structure and physical properties of boron-rich TM (TM=Ti, V, Mn, Zr, Nb, Mo, Tc, Ta, W, Re, Os, and Ir) compounds have been extensively investigated [20][21][22][23][24][25][26][27][28][29][30]. The obtained results showed that these materials possess high bulk and shear moduli.…”

Section: Introductionmentioning

confidence: 99%

Crystal Structure and Physical Properties of HfB4 via First-Principles Calculations

Zhang

Gao

Zhao

et al. 2017

Preprint

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By using the particle swarm optimization algorithm for crystal structure prediction, we reveal a newly orthorhombic Cmcm structure of HfB4, which is more energetically superior to the previously proposed YB4-, ReP4-, FeB4-, CrB4-, and MnB4-type structures in the considered pressure range. The phonon dispersion and elastic constants calculations confirm that the new phase is dynamically and mechanically stable. The calculated large shear modulus (240 GPa) and high hardness (45.7 GPa) imply that the predicted Cmcm-HfB4 is a potential superhard material. Meanwhile, the directional dependences of the Young's modulus, bulk modulus, and shear modulus for HfB4 are systematically investigated. Further analyses of the density of states and electronic localization function indicate that the strong B-B and B-Hf covalent bonds greatly contribute to its high hardness and stability.

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