Ab initio investigation of electronic structure and optical properties of IrSn 4 .

We have examined the electronic structure and optical properties of intermetallic IrSn 4 for three polymorphic modifications, α-IrSn 4 , β-IrSn 4 , and γ-IrSn 4 , utilizing the first-principles PAW-PBEsol-GGA and FP-LAPW-LSDA methods. The obtained electronic structure data reveal clear-cut differences between α-IrSn 4 and the remaining morphs. This observation may be used to explain the appearance of superconductivity in β-IrSn 4 , and also provides reasonable grounds to suspect eventual superconductivity in γ-IrSn 4 . Therefore, it is highly desirable to carry out extended measurements on γ-IrSn 4 at lower temperatures.