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Based on density functional theory, we have systematically studied the structural stability, mechanical properties and chemical bonding of the transition metal borides M3B4 (M=Ti, V, Cr, Zr, Nb, Mo, Hf, Ta, and W) for the first time. All the present studied M3B4 have been demonstrated to be thermodynamically and mechanically stable. The bulk modulus, shear modulus, Youngs modulus, Poissons ratio, microhardness, Debye temperature and anisotropy have been derived for ideal polycrystalline M3B4 aggregates. In addition, the relationship between Debye temperature and microhardness has been discussed for these isostructral M3B4. Furthermore, the results of the Cauchy pressure, the ratio of bulk modulus to shear modulus, and Poissons ratio suggest that the valence electrons of transition metals play an important role in the ductility of M3B4. The calculated total density of states for M3B4 indicates that all these borides display a metallic conductivity. By analyzing the electron localization function, we show that the improvement of the ductility in these M3B4 might attribute to the decrease of their angular bonding character.
Ultraviolet-photoemission (UPS) measurements and supporting specific-heat, thermal-expansion, resistivity and magnetic-moment measurements are reported for the magnetic shape-memory alloy Ni$_2$MnGa over the temperature range $100K < T < 250K$. All m
MXenes, a family of two-dimensional transition metal carbides and nitrides, have various tunable physical and chemical properties. Their diverse prospective applications in electronics and energy storage devices have triggered great interests in scie
Synchrotron X-ray total scattering studies of structural changes in rutile VO2 at the metal-insulator transition temperature of 340 K reveal that monoclinic and tetragonal phases of VO2 coexist in equilibrium, as expected for a first-order phase tran
The electronic structure in alkaline earth AeO (Ae = Be, Mg, Ca, Sr, Ba) and post-transition metal oxides MeO (Me = Zn, Cd, Hg) is probed with oxygen K-edge X-ray absorption and emission spectroscopy. The experimental data is compared with density fu
Infrared (IR) transmittance tunable metal-insulator conversion was demonstrated on glass substrate by using thermochromic vanadium dioxide (VO2) as the active layer in three-terminal thin-film-transistor-type device with water-infiltrated glass as th