Effect of pressure on the structural, electronic and mechanical properties of ultraincompressible W 2 B.

The crystal structures of W 2 B have been extensively investigated by the swarm structure searching method at ambient and high-pressure conditions. Our calculated thermodynamic enthalpy data suggests that the tetragonal phase with I 4/ m symmetry is the most stable at 0-50 GPa. The theoretical elastic properties and phonon spectroscopy confirmed that I 4/ m W 2 B is both mechanically and dynamically stable. The calculated band structure and density of states show that I 4/ m W 2 B is metallic and the electronic properties are sensitive to changes in external pressure with the occurrence of an electronic topological transition. The simulated high elastic modulus, hardness and strain-stress relationships reveal that W 2 B exhibits excellent ultraincompressible properties and high strength. The combination of superior conductivity and mechanical properties reveals that W 2 B can be used for hard coatings and electrical measurements.