The structure, mechanical and electronic properties of WSi2 from first-principles investigations.

Tungsten disilicide (WSi 2) is an attractive advanced functional material, which is regarded as the potential thermoelectric devices, energy storage system and aerospace etc. However, the correlation between structure and the related performances of WSi 2 is not well understood. To solve those problems, we apply first-principles calculations to study crystal structure, electronic properties, elastic properties and electronic structure of four possible WSi 2. We demonstrate the WSi 2 with C54 TiS 2 -type orthorhombic structure (Fddd , No.70) is a dynamically stable. These results show that MoSi 2 -type C11 b tetragonal structure is more thermodynamically stable than that of the other structures. Importantly, MoSi 2 -type C11 b , TiSi 2 -type C49 and HfSi 2 -type C54 structures show electronic properties because of band overlap between the valence band and the conduction band near the Fermi level. However, NbSi 2 -type C40 structure shows a semiconductor property with a band gap of 0.049 eV. We further find that MoSi 2 -type C11 b structure shows the strong shear deformation resistance and high elastic stiffness due to the pyramidal bonding state. WSi 2 with TiSi 2 -type C54 structure exhibits better ductile in comparison to the other structures. • The structural, mechanical and electronic properties of WSi 2 are studied. • One new WSi 2 orthorhombic structure (C 54) is predicted. • WSi 2 with hexagonal structure (C40) shows a semiconductor property within a band gap of 0.049eV. • WSi 2 with C11 b structure shows the strong mechanical properties compared to other structures. [ABSTRACT FROM AUTHOR]