Density-functional theory study on the electronic properties of laves phase superconductor CaIr_2

In this work we have used density-functional theory methods such as full-potential local orbital minimum basis (FPLO) and ELK-flapw to study the electronic structure of newly discovered Laves phase superconductor CaIr₂. The calculation of density of states (DOS) indicates that the bands near Fermi level are mostly occupied by the d-electrons of iridium. The simulation of de Haas-van Alphen (dHvA) effect has been performed by using Elk code to check the Fermi surface topology. The results show that there exist four Fermi surfaces in CaIr₂, including two electron-type and two hole-type surfaces. The optical response properties of CaIr₂ have been calculated in the dipole-transition approximations combined with including intra-band Drude-like terms. In the optical spectrum σ (ω) shows that the crossover from intra-band to inter-band absorption occur near 1.45 eV. Further analysis on the electron energy loss spectra (EELS) matches the conclusion from that of optical conductivity σ (ω).