First-principles study of the structural, electronic, and optical properties of Y-doped SrSi2

The structural, electronic, and optical properties of Y-doped SrSi2 crystals were studied by first-principles calculations in the framework of density-functional theory. Indeed doping with Y induced the structural compression evidently, at the same time, a structural transition was observed from cubic to tetragonal configuration for Sr0.5Y0.5Si2. Band structure calculations revealed that the replacement of Sr by Y made SrSi2 undergo semiconductor-metal transition, meanwhile, the metallic characteristics of Y-doped SrSi2 was enhanced with increasing the Y content. This encouraging finding suggests that further improvements of the thermoelectric performance on the SrSi2-based alloys may be made by increasing Y content; in a word, this changes would make this system attractive for possible candidates for thermoelectric applications. Finally, the dielectric function, absorption spectrum, and energy-loss spectrum were calculated and analyzed for Y-doped SrSi2 crystals, which show that it is a promising dielectric material. (C) 2013 American Institute of Physics. [http://dx.doi.org/10.1063/1.4788715]