Large anisotropy in the optical conductivity of YNi₂B₂C

The optical properties of YNi₂B₂C are studied by using the first-principles full-potential linearized augmented plane-wave method within the local density approximation. Anisotropic behavior is obtained in the optical conductivity, even though the electronic structure shows three-dimensional character. A large peak in σ_z is obtained at 2.4 eV. The anisotropic optical properties are analyzed in terms of interband transitions between energy levels, and it is found that the Ni site plays an important role. The electronic energy loss spectroscopy spectra are also calculated to help elucidate the anisotropic properties in this system.