We report on the results of calculation of low-energy dielectric response and optical properties of MgB2. The calculations have been performed with full inclusion of the ab initio electron band structure making use of random-phase and time-dependent local-density approximations. The role of local-field and exchange-correlation effects in MgB2 dielectric function is thoroughly examined. Index of refraction, extinction coefficient, and normal-incidence reflectivity exhibiting strong anisotropy were calculated for electromagnetic waves polarized along the a∗ and c∗ axes by using the evaluated electron-density-response functions. Our results are in good agreement with recent x-ray and optical measurements performed on MgB2 single crystals.

We acknowledge the partial support from the University of the Basque Country Grant No. GIC07IT36607, the Departamento de Educación del Gobierno Vasco, and the Spanish Ministerio de Ciencia y Tecnología MCyT Grant No.FIS200766711C0101. The work of V.M.S. is sponsored by the IKERBASQUE Foundation.

Peer reviewed