First-principles calculation of structural, thermodynamic and mechanical properties of 5d transitional metal triborides TMB3 (TM=Hf–Au)

Abstract

a b s t r a c tDue to their useful physical and chemical characteristics, transitional metal borides have attracted much attention. In this study, the structural, thermodynamical, mechanical, dynamical and electronic properties of 5d transitional metal triborides TMB 3 (TM ¼ HfeAu) are investigated by density functional theory. For each triboride, five structures are considered, i.e., m-AlB 2 (modified AlB 2 ), OsB 3 , FeB 3 , WB 3 and TcP 3 structures. The calculated lattice parameters are in good agreement with previously theoretical results. Thermodynamic stability of compounds is predicted and the formation enthalpy increases from TaB 3 to AuB 3 . The calculated phonon dispersion curves demonstrate that each TMB 3 in the most stable structure is dynamically stable. The calculated density of states shows that they are all metallic. Among the studied compounds, OsB 3 -ReB 3 (OsB 3 -ReB 3 represents ReB 3 in OsB 3 structure, the same hereinafter) has the largest shear modulus (261 GPa), bulk modulus (355 GPa) and Young modulus (630 GPa). WB 3 -WB 3 has the second largest shear modulus (257 GPa). This suggests that OsB 3 -ReB 3 and WB 3 -WB 3 might be potential ultra-incompressible and superhard materials.

Explorations of boron-based materials through theoretical simulations

“…Boron-based materials have been extensively studied, mainly due to their excellent mechanical properties. Binary boron-based materials is a well-explored field of science where metal (typically a transition metal denoted M) diborides MB 2 [25] , triborides MB 3 [26] , and tetraborides MB 4 [27,28] have all been extensively studied for industrial applications [29][30][31][32][33] . Higher-order boron-based materials, i.e., ternary, quaternary, and quintenary, have recently gained interest as more components often increase the possibility of tuning the materials' properties.…”